Fused Galactopyranoside Scaffold

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Synthesis of Sialyl LewisX Glycomimetics Bearing a Bicyclic 3-O, 4-C-Fused Galactopyranoside Scaffold Ryan Daniel Simard, Mathieu Joyal, Laura Gillard, Gianna Di Censo, Wael Maharsy, Janie Beauregard, Pina Colarusso, Kamala D. Patel, Michel Prévost, Mona Nemer, and Yvan Guindon J. Org. Chem., Just Accepted Manuscript • DOI: 10.1021/acs.joc.9b01075 • Publication Date (Web): 15 May 2019 Downloaded from http://pubs.acs.org on May 15, 2019

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The Journal of Organic Chemistry

Synthesis of Sialyl LewisX Glycomimetics Bearing a Bicyclic 3-O, 4-CFused Galactopyranoside Scaffold Ryan D. Simard†,‡, Mathieu Joyal§, Laura Gillard†, Gianna Di Censo†, Wael Maharsy§, Janie Beauregard§, Pina Colarusso∥, Kamala D. Patel∥*, Michel Prévost†*, Mona Nemer§*, and Yvan Guindon†,‡,§* †Bio-organic

Chemistry Laboratory, Institut de Recherches Cliniques de Montréal, Montréal, Québec H2W 1R7, Canada ‡Department of Chemistry, Université de Montréal, Montréal, Québec H3C 3J7, Canada §Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada ∥Live

Cell Imaging Laboratory, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta T2N 4N1, Canada ABSTRACT: Reported herein is the synthesis of sialyl LewisX analogues bearing a trans-bicyclo[4.4.0] dioxadecane modified 3-O, 4-C-fused galactopyranoside scaffold that locks the carboxylate pharmacophore in either the axial or equatorial position. This novel series of bicyclic galactopyranosides are prepared through a stereocontrolled intramolecular cyclization reaction that has been evaluated both experimentally and by DFT calculations. The cyclization precursors are obtained from β-Dgalactose pentaacetate in a 9-step sequence featuring a highly diastereoselective equatorial alkynylation and Cu(I) catalyzed formation of the acetylenic α-ketoester moiety. Preliminary biological evaluations indicate improved activity as P-selectin antagonists for the axially configured analogues as compared to their equatorial counterparts.

INTRODUCTION The design of small-molecule antagonists requires a fine balance between plasticity and pre-organization to mimic the bioactive conformation of endogenous ligands. This strategy is particularly effective with complex carbohydrate ligands to minimize entropic penalties upon receptor binding.1 Analogues of sialyl LewisX (sLeX) interfere with the recruitment of immune cells along the endothelial vasculature at sites of inflammation.2-4 These antagonists compete with the binding of the sLeX tetrasaccharide (Figure 1a), present at the surface of leukocytes on glycoprotein ligands ESL-1 and PSGL-1, to the selectins (E and P).5-6 Interfering with these adhesion events offers novel approaches to control the excessive influx of immune cells characteristic of several inflammatory diseases.7 Moreover, metastatic cancers that take advantage of this extravasation mechanism could be prevented from adhering and translocating to distal sites.8 GMI-1070 (Figure 1b), an E-selectin antagonist, is currently in Phase III evaluation for treatment of vascular occlusions in patients with sickle cell disease.9 The bound conformations of sLeX to E- and P-selectin are well defined by molecular modeling and NMR methods.10-14 A significant chemical modification in sLeX glycomimetics is the replacement of the GlcNAc moiety with a functionalized cyclohexyl (Figure 1b) or tartrate diester tether (Figure 1c).4, 15

HO OH OH Me O HO OH NHAc HO OH O O AcHN OH O O O O HO OH CO2H OH OH

a) Sialyl LewisX (sLeX)

Gal

NeuAc

NH

HO OH O

OH O

HO O

OH O

O O

Ph

BzO O

CO2H

O OH O OBz

O

NH

OH

Me

O

O

OiPr OiPr

O O

SO3Na

NaO3S SO3Na

d) This work: HO OH

HO OH Me

O

NH

HN

c) Guindon et al. 2012

O

O O

N H NH O

OBz

CO2Na

GlcNAc

O

b) Rivipansel (GMI-1070)

Me

Fuc

HO Y

O

O OR2 O

OH O O

O OiPr OiPr

OR1 O X H Y = H, X = CO2H Y = CO2H, X = H 1: R1 = Bz; R2 = H 3: R1 = Bz; R2 = H 4: R1 = R2 = Bz 2: R1 = R2 = Bz

Figure 1. Sialyl LewisX and glycomimetics thereof

ACS Paragon Plus Environment

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In both cases, the fucose and galactose saccharides are forced to adopt a gauche relationship that favorably orients their pharmacophoric hydroxyls in the receptor.16 The conformational bias of the tartrate esters has been suggested to originate from stereoelectronic effects (gauche effect and dipole-dipole minimization).17 Several reports have also highlighted the importance of orienting the carboxylate of the NeuAc moiety, which is central to this study.18-19 Analogues exploiting the preorganization of the carboxylic acid fragment may benefit from enhanced binding. A gain in affinity was demonstrated when the sialic acid was simplified with derivatives of lactic acid bearing a cyclohexyl or benzyl substituent.13 Structure overlap of bound sLeX with bicyclic galactopyranoside scaffolds suggested that an axially configured carboxylate could mimic the bound orientation. In contrast, equatorially configured glycomimetics were expected to bind less favorably to the receptor.20 Formation of a bicyclic system would lock the carboxylic acid moiety in either an axial (1 and 2, Figure 1d) or equatorial (3 and 4, Figure 1d) configuration allowing this significance to be determined. The preparation of these bicyclic compounds in a stereospecific manner represented a major synthetic challenge. Careful consideration of the ring junctions to preserve the pharmacophoric hydroxyl at C4 of galactose necessitated a 3-O, 4-C-fusion to be envisioned. The synthesis of functionalized transbicyclo[4.4.0]galactopyranoside 5 (Scheme 1), to our knowledge, has not been reported. Annulated pyranosides have been recently described, however, relying mainly on ring closing metathesis (RCM) reactions.21-27 A series of gluco- and galacto- cis- and trans-oxabicyclo[4.4.0]decane derivatives, featuring a 4-C, 6-O-fused ring scaffold, were elegantly described by Crich et al.28-29 Taking these strategies into consideration, formation of the bicyclic galactopyranoside 6 was planned from the RCM of diene 7.

Scheme 1. Retrosynthetic analysis of trans-bicyclo[4.4.0]-galactopyranoside 5 O R

O CO2Bn

CO2Bn

MgBr

OBn O

HO SEt

OBn O

O

OBz

Grignard CO2Bn 7 Vinylation

8

TfO SEt

OBz

R

HO

OBn O

HO

SEt

OBz

Regioselective O-alkylation

9

6

4

7 8

O

5

HO HO

2

3

O

H

RO

OBz

O

O

CO2H 5

Intramolecular Cyclization RO SEt

9

O OBn

MsO

OBz

9

6 O BnO

Cl O

HO PMBO

OTBDPS O SEt OPMB 12

Li

RESULTS AND DISCUSSION The reaction sequence to generate the targeted bicyclic scaffolds began with construction of the quaternary center at C4 (Scheme 2). The C6-O-TDBPS protected intermediate 12 was first prepared from known thiogalactoside 1330 through benzylidene removal followed by silylation of the primary alcohol. Albright-Goldman oxidation with acetic anhydride and DMSO, and subsequent treatment with ethynyl magnesium bromide led to an unsatisfactory 3:2 ratio of C4 diastereomers 11a,b. Gratifyingly, treatment with lithium TMS-acetylide provided the equatorial alkyne 15 in a diastereomeric ratio of 20:1 with a 93% isolated yield. The equatorial selectivity was confirmed by NOE correlations of E-olefin 16, which was formed through a Red-Al reduction in 75% yield.31-32 High stereoselectivity likely originates from a preferred bottom face attack on the carbonyl to avoid electrostatic clashing of the carbonylcomplexed lithium acetylide with the top face substituents.33-34

Scheme 2. Stereoselective alkynylation reaction at C4 Ph

1. TsOH, MeOH/CH2Cl2 2. TBDPSCl, Imidazole, DMF

O O PMBO

OR

SEt

1

planned Grignard addition to ketone 8 resulted predominantly in elimination of the C2-O-benzoate, while the C3-O-alkylation of diol 9 was difficult, likely due to the sterically hindered quaternary center at C4. We developed a strategy capitalizing on the installation of an alkyne at C4 (11) from protected galactoside 12. This alkyne could then be extended to an acetylenic keto-ester through a Cu(I) catalyzed addition of benzyl chlorooxalate. Diastereoselective reduction of the ketone moiety would lead to the two C9 diastereoisomers. After alkyne reduction and subsequent mesylation (10), intramolecular cyclization could then afford the bicyclic intermediate 6 with axial or equatorial ester orientations. This approach unveiled an intriguing stereocontrolled cyclization giving rise to the axial isomer from both mesylate diastereomers. The origin of selectivity for this reaction, which is proposed to follow Curtin-Hammett kinetics, was studied experimentally and computationally.

O

SEt OPMB 13 (ref 30)

Ring-Closing Metathesis

TMS

HO PMBO

Oxidation & Alkynylation

HO O

OTBDPS O SEt OH

OBn

10

Alkynylation & Reduction OTBDPS O SEt OPMB 11

Unfortunately, the elaboration of either the C4 vinyl (9) or the C3-O-allylic fragments (8) were unsuccessful. The

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PMBO

Ac2O, DMSO, 65 °C (93%) CHCMgBr, THF, MS 3Å, -78 °C

H8 HO OTBDPS TMS O PMBO SEt H7 H5 OPMB H3 NOE 16

Red-Al, Et2O, 0 °C



4

(89% two steps)

OTBDPS O SEt OPMB 11a: X = OH, Y = CCH 11b: X = CCH, Y = OH

X 4 Y PMBO

HO

(85%, 3:2 dr)


O PMBO

TMSCCLi, THF, -78 °C (93%, 20:1 dr)

(75%)

HO TMS

4

PMBO 15

OTBDPS O SEt OPMB

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The reaction sequence from alcohol 12 (oxidation, alkynylation, and deprotection) could be performed in tandem to generate galactoside 11a in an 81% overall yield (Scheme 3). In order to avoid formation of unwanted spirocyclic compounds during the planned intramolecular cyclization, protection of the C4 hydroxyl was evaluated. This tertiary hydroxyl was inert to standard protection conditions. By capitalizing on the alkoxide generated in situ during the alkynylation reaction, treatment with TMSCl provided the fully protected galactoside 17 in 87% overall yield. A Cu(I)-catalyzed alkynylation with benzyl chlorooxalate31 generated propargylic α-keto esters 18 or 19 in moderate to good yields (81 and 66%).

hydroxyester 20b gave a 4:1 ratio in favor of the R-isomer 22a, in a 72% yield. This suggested that the reduction with (R)-BINAL-H formed the S-configured alcohol. In addition, these results reinforced the necessity for a protecting group on the C4 tertiary alcohol to avoid spirocycle formation.

Table 1. Asymmetric reduction of acetylenic αketoesters R 1O

O

PMBO OBn

O

HO PMBO


R 1O

OTBDPS O SEt PMBO OPMB Yield over three steps: 11a: R1 = H (81%) 17: R1 = TMS (87%)

3. K2CO3, MeOH, 1 h

O HO

9

R 1O

(R)

PMBO OBn a R 1O HO

O

9

O

(S)

PMBO OBn b

Cl

OTBDPS O SEt OPMB

BnO

CuCl cat., NEt3, THF

O O

Table 1 OTBDPS O SEt OPMB 20: R1 = H 21: R1 = TMS

O

R 1O

PMBO OBn 18: R1 = H 19: R1 = TMS

OTBDPS O SEt OPMB (81%) (66%)

Stereoselective reduction of the α-ketoester was first examined with chiral reducing agents (Table 1). Treatment of ketone 18, bearing a free hydroxyl at C4, with (R)-BINALH at -78 °C furnished propargylic-α-hydroxyester 20b in a 9:1 ratio in favor of the S-diastereoisomer (entry 1).36 (S)BINAL-H afforded the R-configured alcohol 20a in a similar yield and ratio (entry 2). The initially planned intramolecular SN2 displacement of the latter would generate the axial carboxylic product 5b. Poor stereoselection was observed when treating C4-O-TMS protected ketone 19 with (S)-BINAL-H, suggesting unfavorable clashing of the silyl group with the chiral reagent (entry 3). Alternatively, reduction in the presence of LiAlH(tBuO)3 gave an expected 1:1 mixture of alcohols 20 and 21 from ketones 18 and 19 respectively (entries 4 and 5). The absolute configuration of acetylenic α-hydroxyesters 20a and 20b was determined through diimide reduction of the internal alkyne to the cis-olefin, followed by a chemoselective mesylation of the C9 secondary alcohol (Scheme 4). Displacement of the mesylate by the tertiary alcohol at C4 formed mixtures of 5-membered spirocycles 22a and 22b. Treatment of α-hydroxyester 20a gave an 8:1 ratio in favor of the S-isomer 22b, thus suggesting reduction with (S)-BINAL-H indeed formed the R-configured alcohol as the major product. The stereochemical assignment is supported by 2D NOE correlations between the C9 proton and either the C6 or CH2 protons of the C3-O-PMB ether moiety (See SI). Using the same reaction conditions, α-

R 1O

9

OTBDPS O SEt OPMB

(R)

PMBO O OBn a R 1O HO

18: R1 = H 19: R1 = TMS

OTBDPS O SEt OPMB

9

(S)

Scheme 3. Tandem alkynylation sequence and sidechain extension at C4 1. Ac2O, DMSO, 65 °C 2. TMSCCLi, THF, -78 °C; NH4Cl(aq) or TMSCl, 0 °C

HO

OTBDPS O SEt OPMB

PMBO O 20: R1 = H OBn 21: R1 = TMS b

Entry

Ketone

Reducing Agenta

Alcohol

Ratiob (a : b)

Yieldc (%)

1

18

(R)-BINAL-H

20

1:9

85

2

18

(S)-BINAL-H

20

9:1

82

3d

19

(S)-BINAL-H

21

2:1

n.d.

4

18

LiAlH(tBuO)3

20

1:1

94

5

19

LiAlH(tBuO)3

21

1:1

97

Conditions: BINAL-H (3 equiv) or LiAlH(OtBu)3 (1.1 equiv), THF (0.1 M), -78 °C, 3 h. bDetermined by 1H NMR analysis of crude reaction mixture. cIsolated yield. dPartial C4-O-TMS cleavage observed. n.d.: not determined. a

Scheme 4. configuration precursors

Assignment of and preparation

1. TrisylNHNH2, Et2O, Reflux

20a or 20b

2. MsCl, pyr., CH2Cl2, 40 °C

BnO H

α-hydroxyester of cyclization

O (R) 9 O

PMBO

O OTBDPS O SEt OPMB

OBn H (S) 9 O

PMBO

22a (72%) 4:1 dr from 20b HO O

HO

9 (R)

PMBO OBn

OTBDPS O SEt OPMB

22b (76%) 8:1 dr from 20a

TMSO OTBDPS a) TMSOTf, 2,6-Lut. HO b) PPTS, MeOH O (R) SEt PMBO O OPMB OBn

20a

OTBDPS O SEt OPMB

21a (87%) c) TrisylNHNH2, Et2O, Reflux

OBn O

(R)

OMs PO OTBDPS O SEt HO OH

24a (72%)

d) MsCl, NEt3, CH2Cl2 e) DDQ, CH2Cl2, H 2O

OBn O

OH PO

(R)

PMBO

OTBDPS O SEt OPMB

23a (68%)

P = TMS

OBn HO

HO O

(S)

PMBO OBn 20b


O d, e

OTBDPS c a, b O 23b 21b SEt (87%) (74%) (92%) OPMB

(S)

OMs PO OTBDPS O SEt HO OH 24b


Bis-protection of the α-hydroxy esters 20a and 20b was carried out in the presence of TMSOTf and 2,6-lutidine at low temperature, with subsequent removal of the secondary TMS moeity under mildly acidic conditions. Through thermal decomposition of trisylhydrazide,37-38 the alkynes were reduced to the corresponding cis-alkenes 23a and 23b (68 and 87% yields). The sterically congested nature of the disubstituted alkyne prevented complete saturation to the alkane under conventional hydrogenation conditions. Subsequent treatment with MsCl and NEt3 followed by oxidative cleavage of the 2,3-di-O-PMB ethers using DDQ formed the cyclization precursors 24a (9R) and 24b (9S) in 72 and 74% yields. With the mesylate precursors 24a,b in hand, the targeted intramolecular cyclization reaction to access bicyclic galactosides 25a,b was investigated (Table 2). A first cyclization attempt using mesylate 24a with a mild base in refluxing dichloromethane (entry 1) resulted in an inseparable 1:2 mixture of spirocycles 26a and 26b in 35% yield. Seemingly, an isomerization of the mesylate and migration of the silyl ether to the less hindered C3 hydroxyl had occurred. An intriguing observation was that either C9 epimer cyclized in refluxing acetonitrile (entries 2 and 3) to provide spirocycles favoring the R-diastereomer 26a in high yield, in a 3:1 or 5:1 ratio.

Table 2. Intramolecular cyclization to access transbicyclo[4.4.0]galactopyranoside 25 Entry

Mesylate

Temp

24a : 24b

(°C)

Solvent

Ratioa,b

Yieldc

(a : b)

(%)

Remarkably, the silyl group migration could be suppressed by switching the solvent to toluene, and with heating at 100 oC, the desired axial bicycle 25b was formed in a 69% yield with an excellent 15:1 ratio (entry 4). When these conditions were carried out using S-mesylate 24b (entry 5), a 7:1 ratio also in favor of the axial isomer was observed. Gratifyingly, an enhanced axial selectivity was observed from a 1:1 mixture of mesylates 24a,b (entry 6), suggesting that stereoselective reduction of the acetylenic ketoesters was not required. Under extended refluxing in toluene, the α,β-unsaturated ester 27 was obtained in 64% yield (entry 7). The intriguing preference for the cyclized axial galactopyranoside 25b from different mesylate mixtures prompted us to seek computational insight (Gaussian 09)39 into the origin of this induction (Scheme 5). At the M062x/6-31G*/6-311+G** level of theory,40-41 cyclization of simplified mesylates 28a and 28b, in the presence of NMe3 as the base, was found to proceed through lowest SN2 transition structures TS B and TS C.

Scheme 5. Relative free energies (kcal/mol) for the intramolecular cyclization reaction at 80 oC in toluene, relative to 28b at the M062x/6-31G*/6311+G** level of theory and corrected with Truhlar’s quasiharmonic entropic correction45-47 SiMe3 SMe OH OH OMs H MsO CO Me 2 TS A O O

Me

OBn

O

OBn OBn O O OMs (R) (S) O OTBDPS O OTBDPS PO OTBDPS + O O O SEt SEt SEt TMSO TMSO HO OH OH OH 24a (R) or 24b (S) P = TMS 26a 26b 9

1d

20 : 1

40

CH2Cl2

1:2

35

2

20 : 1

85

MeCN

3:1

84

3

1 : 20

85

MeCN

5:1

77

9


4

TMSO

OTBDPS BnO O SEt + H O O OH H H BnO 25a

20 : 1

100 e

Toluene

5

1 : 20

100 e

6

1:1

100 e

OBn O


1:1

TMSO O O

H

OTBDPS O SEt OH

O

(S)

HO OMs

69

Toluene

1:7

58

Toluene

1 : 13

65

O

O OBn

H

O MeO MsO

TMSO Me

TS A (24.1)

O

SMe O

OH

k1 and k-1 : fast

OMe 28b (0.0)

25b

1 : 15

TMSO

9

7d

TMSO Me

TMSO Me O H H

(R)

HO OMs

O

k3 : slow

NMe3

TMSO Me O

SMe

OH NMe3

H MsO O

TS B (38.7)

O SMe O OH H OMe NMe3

TS C (32.4)

OTBDPS O SEt OH

27

100

Toluene

-

64

aConditions:

Solvent (0.1 to 0.2 M), DIPEA (3 equiv), 2 h. bProduct ratio determined by 1H NMR analysis of crude mixture. cIsolated yield. d16 h. eHeating at 80 °C provided similar yields and ratios, with longer reaction times than 2 h (approx. 9 h).

MeO O

TMSO Me O H

H

TMSO Me O OH

29a (-20.3) (Minor)


SMe

SMe

OH

OMe 28a (1.7)

k2 : slow

NMe3

OBn O

Page 4 of 20

H MeO

O H

O OH

O 29b (-21.5) (Major)

SMe

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The two TS are both significantly higher in energy than the epimerization TS A.48 The rapid epimerization is consistent with 1H NMR spectroscopy studies in deuterated toluene, as well as experimental results that demonstrate the interconversion between mesylates 24a,b at 40 °C, a lower temperature than what is required for the cyclization. This is also in agreement with precedents from the literature for α-halo and hydroxyester interconversions.4244 The TS C leading to the major axial epimer 29b displays a lower relative Gibbs free energy of 32.4 kcal/mol, in comparison to that of TS B for the formation of equatorial product 29a (38.7 kcal/mol). Presumably, minimization of the allylic strain to prevent steric clashing between the ester and the C4-O-TMS group in TS C produces this difference in energy. It is noteworthy that this steric clash is also present in the equatorial product 29a, which is 1.2 kcal/mol higher in energy than 29b. A thermodynamic equilibrium between these two products could therefore also furnish the observed selectivity in favor of 29b. The reversibility barrier through TS A or TS B is, however, quite substantial at 80 oC (53.9 kcal/mol). Moreover, resubmitting the isolated equatorial galactopyranoside 25a in the reaction conditions only led to the corresponding decomposition product 27. The yield of bicyclic galactoside 25b is greater than 50%, independent of the diastereomeric composition of mesylates 24a,b, and both epimers form the α,βunsaturated product 27. Thus, the observed selectivity is not due to selective decomposition of the minor galactoside. Taken together, we propose that the cyclization occurs through a Curtin-Hammett scenario, where it is the relative free energy of the cyclization transition states (TS B and TS C) that is at the origin of the observed selectivity.49 Bicyclic galactopyranosides 25a and 25b were then benzoylated (Scheme 6), a necessary step to favor β-anomer formation in the planned glycosylation through anchimeric participation.

Scheme 6. Deprotection of intramolecular cyclization products

BnO

TMSO O

O

H

H

OTBDPS O SEt OR1

TMSO H

O

BnO

O

OTBDPS O SEt OR1

H

1. HF•NEt3, THF 2. Pd(OH)2, H2, THF (60% two steps)

BzCl, pyr., CH2Cl2 (74%)

25a: R1 = H 30a: R1 = Bz

the

bicyclic

HO

O

O

HO

H3

H9

H BnO

O O

H 32b

OBz

SEt

Me

TMSO H BnO

OBz

BnO

HO

(81%)

O

OH O

O

O O

H

SEt

BzCl, pyr. (87%)

H9

(88%)

H9

O

HO

O

OH O

H3

OBz

HO

SEt

O

O

OR1 O

34

HF•NEt3

TBAF

(94%)

(96%)

Pd(OH)2, H2, THF OH

Me Olefin Migration

HO

O

O OR1 O

O H

OBn BzCl, pyr. (94%)

OBn O O O

OBz

OiPr OiPr

O

37: R1 = H 38: R1 = Bz

Pd(OH)2, H2, THF

HO OH Me

O

O O

OBz O H O 3 1: R1 = H (87%) 2: R1 = Bz (53%)


H

O

BnO OBn

O

5b

O

TMSO

O

H NIS, TMSOTf 3Å MS, -35 °C, 2 h BnO (87%, >20:1 dr)

35: R1 = H 36: R1 = Bz

Me

OBn O O OiPr OTBDPS O OiPr O OBz O

Me

OiPr OiPr

HO OH

31

HO

BnO OBn

HO

OBn Me O O O HO OR1 OiPr O OiPr O O OBz O H O

HO

Pd(OH)2, H2,THF

OTBDPS O SEt OBz

30b

OBz

H

OBn O O

33

H

TBAF, THF

O

BnO OBn

Pd(OH)2, H2, THF (69%)

BzCl, pyr., CH2Cl2 (93%)

OH O

BnO OBn

SEt

HF•NEt3, THF (83%) HO

Scheme 7. Completion of the synthesis of selectin antagonists bearing the transbicyclo[4.4.0]galactopyranoside scaffold

5a

OBn

25b: R1 = H 30b: R1 = Bz

OH O

Removal of the silyl ethers was achieved by using HF∙NEt3, followed by hydrogenation of the endocyclic olefin and debenzylation with Pearlman’s catalyst to form exclusively the annulated galactopyranosides 5a (equatorial) and 5b (axial). The stereochemical configurations of the carboxylates were assigned using their characteristic 1H NMR 3JH,H coupling constants and NOE correlation data between H3 and H9 (See SI). Although the synthetic route achieved exclusive access to the axially configured bicyclic galactopyranoside, we sought to develop a method that could access both diastereomers selectively. By exploiting the observation that the olefin geometry could migrate under basic conditions during the intramolecular cyclization, removal of the silyl ethers of benzoylated isomer 30b in presence of TBAF (~5% wt. H2O) also resulted in migration of the double bond to provide α,β-unsaturated ester 31 in 81% yield. Notably, the hydrogenation occurred exclusively from the bottom face of the bicycle to give equatorial galactopyranoside 5a. The novel selectin antagonists were generated through coupling of the C2-O-benzoate protected galactoside 30b with our previously reported15 fucosylated acyclic tether 33 (Scheme 7). Gratifyingly, in the presence of NIS and TMSOTf, glycoside 34 was obtained in excellent yield (87%) and βselectivity (>20 : 1 dr).

OiPr OiPr

HO

HO O

O H9

H3

O OR1 O

OH

O

O

OiPr OiPr

O

OBz

3: R1 = H (85%) 4: R1 = Bz (93%)

O


By capitalizing on the desilylation strategy described above, protected glycoside 34 was treated with either HF∙NEt3 or TBAF to access both deprotected axial and isomerized unsaturated esters 35 and 37 in excellent yields. We have previously reported the increased bioactivity of selectin antagonists bearing a C4-O-benzoate group.4 The incorporation of the benzoate at C4 was not compatible with our synthetic design due to its propensity to eliminate at the cyclization step. Nonetheless, the mono-protection of primary alcohols 35 and 37 with BzCl to afford the 2,6-Odibenzoylated compounds 36 and 38, was successful (87 and 94% yields). The tri-benzoylated products were not observed due to the encumbered C4 quaternary center. The C6-O-benzoates may provide new hydrophobic interactions within the binding pocket. The final global deprotection step using Pearlman’s catalyst provided the target glycomimetics 1-4 in good to excellent yields (53-93%). Extensive biological evaluation of our selectin antagonists is underway and will be reported in due time. However, preliminary results obtained with 2,6-Odibenzoylated sLeX analogue 2 bearing the axial carboxylic acid and its equatorial isomer 4 show promising antagonist activity. We first evaluated their ability to disrupt adhesion of tagged human leukocytes to immobilized P-Selectin (Figure 2).4, 50 The native ligand, sLeX, had an EC50 of 2.2 mM in this assay, whereas both analogues 2 and 4 displayed markedly lower EC50 values of 20 uM and 40 uM, respectively.

Page 6 of 20

activation of other adhesion molecules (integrins) are also noted. The evaluation of our molecules under flow conditions was done using a parallel plate flow chamber to mimic the hydrodynamic conditions found in the vasculature (Figure 3). Isolated primary human umbilical endothelial cells (HUVEC) were assembled into the flow chamber.53-54 To mobilize P-Selectin, stored in Weibel-Palade bodies of the endothelial cells, histamine was used as the inflammatory stimulus. Neutrophils alone or neutrophils containing compounds 2, 4, or sLeX were perfused across the endothelial cells. Most interestingly, compound 2 and sLeX interfered with neutrophil interactions and firm adhesion, while compound 4 was inactive in this assay. The higher binding affinity noted for the axially oriented carboxylate was less pronounced in the static adhesion assay, potentially pointing to differences in P-Selectin/PSGL-1 affinity between the two assays. These preliminary results suggest that it is indeed the axial carboxylate that better mimics the bioactive conformation of sLeX.

Figure 3. Effect of compounds 2, 4, and sLeX on total neutrophil interactions on histamine-treated ECs.

Figure 2. P-Selectin cell-based adhesion assay. HL-60 cells tagged with Leukotracker were bound to P-SelFc coated Elisa plates. Compounds 2, 4, and sLeX were dissolved in TrisCa buffer and added at concentrations of 0.001 mM to 5 mM or 10 mM. The number of adhered cells decreased in a dosedependent way. Inhibition was calculated as the 100% minus binding observed in the wells. Results are the mean (±SEM) of three independent experiments. *p20:1 ratio of C4 diastereomers. Purification by flash chromatography (Hexanes/Et2O, 60:40) provided 11a (44 g, 81%) as a paleyellow oil. Rf = 0.31 (Hexanes/Et2O, 50:50); [α]D25 +17 (c 0.6, CHCl3); C42H50O7SSi; MW = 727.0000 gmol-1; IR (neat, cm-1) νmax 3451, 3282, 2932, 1613, 1585, 1514, 1249; 1H NMR (500 MHz, CDCl3) δ (ppm) 7.83 – 7.63 (m, 4H), 7.49 – 7.35 (m, 6H), 7.32 (dd, J = 8.6, 3.3 Hz, 4H), 6.86 (dd, J = 8.6, 6.5 Hz, 4H), 4.95 (d, J = 10.5 Hz, 1H), 4.84 (d, J = 10.4 Hz, 1H), 4.81 (d, J = 9.9 Hz, 1H), 4.66 (d, J = 10.0 Hz, 1H), 4.49 (d, J = 9.7 Hz, 1H), 4.22 (dd, J = 11.4, 5.4 Hz, 1H), 4.13 (dd, J = 11.4, 2.0 Hz, 1H), 3.92 (s, 1H), 3.81 (s, 3H), 3.80 (s, 3H), 3.67 (appt, J = 9.2 Hz, 1H), 3.60 (d, J = 8.8 Hz, 1H), 3.50 (dd, J = 5.6, 2.0 Hz, 1H), 2.87 (dq, J = 12.6, 7.4 Hz, 1H), 2.75 (dq, J = 12.6, 7.5 Hz, 1H), 2.44 (s, 1H), 1.35 (t, J = 7.4 Hz, 3H), 1.05 (s, 9H); 13C{1H} NMR (126 MHz, CDCl3) δ (ppm) 159.51, 159.48, 135.9, 135.8, 133.1, 133.0, 130.5, 130.4, 130.1, 129.89, 129.88, 127.87, 127.86, 127.84, 113.93, 113.85, 85.8, 84.8, 83.6, 81.2, 78.2, 76.0, 75.5, 74.5, 71.1, 64.4, 55.43, 55.42, 26.8, 24.4, 19.3, 15.3; HRMS calcd for C42H50O7SSiNa [M+Na+]: 749.2947, found 749.2944 (-0.4 ppm). Ethyl 4-C-ethynyl-6-O-(tert-butyldiphenylsilyl)-2,3-di-O(p-methoxybenzyl)-4-O-trimethylsilyl-1-thio-β-Dgalactopyranoside (17). Following General Procedure A for 11a, crude ketone 14 (46.0 g, 65.6 mmol, 1.00 equiv) was dissolved in anhydrous THF (0.26 L, 0.25 M) and then


Page 9 of 20 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


cannulated dropwise into a freshly prepared solution of lithium (trimethylsilyl)acetylide (0.48 M in THF, 164 mL, 1.20 equiv) at -78 °C. After stirring for 2 h, TMSCl (16.7 mL, 131 mmol, 2.00 equiv) was added dropwise and the reaction was warmed to 25 °C for 2 h. A saturated solution of NH4Cl (350 mL) was added and the aqueous layer was extracted with Et2O (2 x 200 mL). The combined organic layers were washed with brine (400 mL), dried over MgSO4, filtered, and concentrated in vacuo. 1H NMR spectroscopic analysis of the unpurified product indicated the formation of a >20:1 ratio of C4 diastereomers. Treatment with potassium carbonate (13.6 g, 98.1 mmol, 1.50 equiv) in methanol (0.39 L, 0.16 M) provided 17 (46 g, 89%) after flash chromatography (Hexanes/Et2O, 60:40) as a paleyellow oil. Rf = 0.6 (Hexanes/Et2O 70:30); [α]D25 +27 (c 3.1, CHCl3); C45H58O7SSi2; MW = 799.1820 gmol-1; IR (neat, cm-1) νmax 3283, 2932, 1613, 1513, 1246; 1H NMR (500 MHz, CDCl3) δ (ppm) 7.78 – 7.68 (m, 4H), 7.47 – 7.36 (m, 6H), 7.31 (dd, J = 8.6, 3.9 Hz, 4H), 6.87 (dd, J = 8.6, 3.7 Hz, 4H), 4.91 (d, J = 10.6 Hz, 1H), 4.83 (d, J = 10.5 Hz, 1H), 4.78 (d, J = 9.9 Hz, 1H), 4.67 (d, J = 9.9 Hz, 1H), 4.55 – 4.49 (m, 1H), 4.16 (dd, J = 11.2, 2.0 Hz, 1H), 3.92 (dd, J = 11.2, 7.9 Hz, 1H), 3.82 (s, 3H), 3.81 (s, 3H), 3.57 – 3.49 (m, 3H), 2.89 (dq, J = 12.7, 7.4 Hz, 1H), 2.78 (dq, J = 12.7, 7.4 Hz, 1H), 2.35 (s, 1H), 1.38 (t, J = 7.4 Hz, 3H), 1.10 (s, 9H), 0.06 (s, 9H); 13C{1H} NMR (126 MHz, CDCl3) δ (ppm) 159.4, 159.2, 135.82, 135.75, 134.9, 134.1, 133.8, 130.63, 130.56, 130.1, 130.0, 129.6, 127.689, 127.686, 113.9, 113.6, 87.2, 85.1, 84.4, 83.2, 78.2, 76.3, 75.5, 75.2, 72.4, 64.2, 55.4, 55.3, 26.9, 24.7, 19.3, 15.2, 2.1; HRMS calcd for C45H58O7SSi2Na [M+Na+]: 821.3339, found 821.3359 (+3.1 ppm). Ethyl 4-C-(benzyloxycarbonyl-1-oxoprop-2-yn-3-yl)-6-O(tert-butyldiphenylsilyl)-2,3-di-O-(p-methoxybenzyl)-1-thioβ-D-galactopyranoside (18). To a solution of CuCl (413 mg, 4.17 mmol, 0.300 equiv) in anhydrous THF (0.14 L, 0.030 M), NEt3 (5.81 mL, 41.7 mmol, 3.00 equiv) was added. The pale-brown reaction mixture was stirred for 15 minutes before a solution of alkyne 11a (11.1 g, 13.9 mmol, 1.00 equiv) in anhydrous THF (15 mL, 0.92 M) and freshly prepared benzyl chlorooxalate (5.07 g, 27.8 mmol, 2.00 equiv) in anhydrous THF (15.0 mL, 1.85 M) were added in rapid succession. The reaction mixture was stirred for 2 h at 25 °C before the light-orange mixture was poured into a saturated solution of NaHCO3 (150 mL). The aqueous layer was extracted with Et2O (2 x 75 mL). The combined organic layers were washed with brine (150 mL), dried over MgSO4, filtered, and concentrated in vacuo. Purification by flash chromatography (Hexanes/Et2O, 60:40) provided 18 (11 g, 81%) as a pale-yellow oil. Rf = 0.30 (Hexanes/Et2O, 50:50); [α]D25 -17 (c 2.8, CHCl3); C51H56O10SSi; MW = 889.1440 gmol1; IR (neat, cm-1) ν max 2932, 2209, 1740, 1689, 1613, 1514, 1249; 1H NMR (500 MHz, CDCl3) δ (ppm) 7.74 – 7.64 (m, 4H), 7.46 – 7.30 (m, 13H), 7.26 (d, J = 8.6 Hz, 2H), 6.89 (d, J = 8.6 Hz, 2H), 6.79 (d, J = 8.6 Hz, 2H), 5.24 (s, 2H), 4.88 – 4.78 (m, 3H), 4.69 (d, J = 10.0 Hz, 1H), 4.47 (d, J = 9.8 Hz, 1H), 4.44 (s, 1H), 4.17 (dd, J = 11.6, 4.7 Hz, 1H), 4.01 (dd, J = 11.6, 2.2 Hz, 1H), 3.81 (s, 3H), 3.79 – 3.74 (m, 4H), 3.63 (d, J = 8.7 Hz, 1H), 3.48 (dd, J = 4.6, 2.2 Hz, 1H), 2.86 (dq, J = 12.7, 7.4 Hz, 1H), 2.75 (dq, J = 12.6, 7.5 Hz, 1H), 1.36 (t, J = 7.4 Hz, 3H), 1.03 (s, 9H); 13C{1H} NMR (126 MHz, CDCl3) δ (ppm) 168.5, 159.60, 159.56, 158.2, 135.8, 135.7, 134.1, 132.5, 132.4, 130.5, 130.3, 130.13, 130.09, 130.06, 129.7, 129.1, 128.89,

128.87, 128.0, 127.9, 114.0, 113.9, 97.6, 85.0, 84.4, 82.9, 79.9, 78.0, 75.7, 75.6, 72.2, 68.9, 64.7, 55.44, 55.36, 26.7, 24.4, 19.2, 15.4; HRMS calcd for C51H56O10SSiNa [M+Na+]: 911.3261, found 911.3275 (+2.2 ppm). Ethyl 4-C-(benzyloxycarbonyl-1-oxoprop-2-yn-3-yl)-6-O(tert-butyldiphenylsilyl)-2,3-di-O-(p-methoxybenzyl)-4-Otrimethylsilyl-1-thio-β-D-galactopyranoside (19). To a solution of CuCl (115 mg, 1.16 mmol, 0.300 equiv) in anhydrous THF (39 mL, 0.030 M), NEt3 (1.62 mL, 11.6 mmol, 3.00 equiv) was added. The pale-brown solution was stirred for 15 minutes before alkyne 17 (3.10 g, 3.88 mmol, 1.00 equiv) in anhydrous THF (10 mL, 0.39 M), and freshly prepared benzyl chlorooxalate (1.54 g, 7.76 mmol, 2.00 equiv) in anhydrous THF (10 mL, 0.78 M) were added in rapid succession. The reaction mixture was stirred for 2 h at 25 °C before the light-orange mixture was poured into a saturated solution of NaHCO3 (60 mL). The aqueous layer was extracted with Et2O (2 x 30 mL). The combined organic layers were washed with brine (100 mL), dried over MgSO4, filtered, and concentrated in vacuo. Purification by flash chromatography (Hexanes/Et2O, 60:40) provided 19 (2.5 g, 66%) as a pale-yellow oil. Rf = 0.42 (Hexanes/Et2O, 50:50); [α]D25 -13 (c 3.6, CHCl3); C54H64O10SSi2; MW = 961.3260 gmol-1; IR (neat, cm-1) νmax 2956, 2217, 1739, 1685, 1605, 1519, 1240; 1H NMR (500 MHz, CDCl3) δ (ppm) 7.63 (dd, J = 17.9, 6.5 Hz, 4H), 7.40 – 7.28 (m, 13H), 7.18 (d, J = 8.6 Hz, 2H), 6.86 (d, J = 8.6 Hz, 2H), 6.75 (d, J = 8.6 Hz, 2H), 5.26 – 5.18 (m, 2H), 4.83 – 4.74 (m, 2H), 4.72 (d, J = 10.8 Hz, 1H), 4.64 (d, J = 10.0 Hz, 1H), 4.47 (d, J = 8.8 Hz, 1H), 3.93 (dd, J = 11.3, 2.7 Hz, 1H), 3.86 (dd, J = 11.3, 7.4 Hz, 1H), 3.80 (s, 3H), 3.76 (s, 3H), 3.60 – 3.45 (m, 3H), 2.84 (dq, J = 12.7, 7.4 Hz, 1H), 2.74 (dq, J = 12.7, 7.5 Hz, 1H), 1.35 (t, J = 7.4 Hz, 3H), 1.01 (s, 9H), 0.02 (s, 9H); 13C{1H} NMR (126 MHz, CDCl3) δ (ppm) 168.1, 159.5, 159.4, 158.0, 135.8, 135.7, 134.1, 133.6, 133.4, 130.6, 130.2, 130.1, 129.84, 129.79, 129.77, 129.2, 129.0, 128.9, 127.793, 127.788, 113.9, 113.7, 97.8, 85.6, 85.2, 83.9, 83.6, 78.1, 76.0, 75.4, 73.3, 68.9, 63.9, 55.4, 55.3, 26.9, 25.0, 19.3, 15.2, 1.9; HRMS calcd for C54H64O10SSi2Na [M+Na+]: 983.3656, found 983.3680 (+2.9 ppm). Compounds from Table 1. Ethyl 4-C-((1R)benzyloxycarbonyl-1-hydroxyprop-2-yn-3-yl)-6-O-(tertbutyldiphenylsilyl)-2,3-di-O-(p-methoxybenzyl)-1-thio-β-Dgalactopyranoside (20a). To a freshly prepared solution of (S)-BINAL-H [36] in anhydrous THF (0.31 M, 1.9 mmol, 3.0 equiv), at -78 °C, acetylenic α-ketoester 18 (0.58 g, 0.65 mmol, 1.0 equiv) dissolved in THF (6.5 mL, 0.10 M) was added dropwise. After stirring for 3 h, methanol (2 mL) followed by a saturated solution of NH4Cl (10 mL) were added. The aqueous layer was extracted with ethyl acetate (2 x 10 mL) and the combined organic layers were washed with brine (20 mL), dried over MgSO4, filtered, and concentrated in vacuo. 1H NMR spectroscopic analysis of the unpurified product indicated the formation of a 9:1 ratio of diastereomers. Purification by flash chromatography (Hexanes/Et2O, 50:50) provided 20a (0.55 g, 96%) as a white foam. Rf = 0.20 (Hexanes/Et2O, 50:50); [α]D25 +2.8 (c 3.4, CHCl3); C51H58O10SSi; MW = 891.1600 gmol-1; IR (neat, cm-1) νmax 3446, 2936, 1750, 1613, 1514, 1249; 1H NMR (500 MHz, CDCl3) δ (ppm) 7.76 – 7.70 (m, 4H), 7.46 – 7.35 (m, 7H), 7.31 (d, J = 8.6 Hz, 2H), 7.29 – 7.21 (m, 4H), 7.21 (dd, J = 6.7, 3.4 Hz, 2H), 6.87 (d, J = 8.6 Hz, 2H), 6.83 (d, J =



8.7 Hz, 2H), 5.17 (d, J = 12.1 Hz, 1H), 5.07 (d, J = 12.0 Hz, 1H), 4.87 – 4.75 (m, 3H), 4.72 (d, J = 10.5 Hz, 1H), 4.65 (d, J = 10.0 Hz, 1H), 4.46 (d, J = 9.8 Hz, 1H), 4.17 (dd, J = 11.4, 5.4 Hz, 1H), 4.09 – 4.01 (m, 1H), 3.97 (s, 1H), 3.81 (s, 3H), 3.79 (s, 3H), 3.67 (dd, J = 9.8, 8.8 Hz, 1H), 3.51 (d, J = 8.8 Hz, 1H), 3.43 (dd, J = 5.3, 2.0 Hz, 1H), 2.92 – 2.79 (m, 2H), 2.80 – 2.69 (m, 1H), 1.35 (t, J = 7.4 Hz, 3H), 1.03 (s, 9H); 13C{1H} NMR (126 MHz, CDCl3) δ (ppm) 169.8, 159.47, 159.46, 135.8, 135.7, 134.6, 132.91, 132.87, 130.5, 130.3, 130.10 130.08, 130.06, 129.9, 128.9, 128.8, 128.5, 127.95, 127.88, 113.9, 113.8, 85.6, 85.4, 84.8, 81.4, 80.8, 78.1, 75.8, 75.5, 71.3, 68.4, 64.4, 61.5, 55.42, 55.39, 26.8, 24.3, 19.2, 15.4; HRMS calcd for C51H58O10SSiNa [M+Na+]: 913.3418, found 913.3405 (0.8 ppm). Ethyl 4-C-((1S)-benzyloxycarbonyl-1-hydroxyprop-2-yn-3yl)-6-O-(tert-butyldiphenylsilyl)-2,3-di-O-(pmethoxybenzyl)-1-thio-β-D-galactopyranoside (20b). Following a similar procedure as in 20a, to a solution of (R)BINAL-H [36] in anhydrous THF (0.31 M, 1.4 mmol, 3.0 equiv), acetylenic α-ketoester 18 (0.41g, 0.46 mmol, 1.0 equiv) dissolved in THF (4.6 mL, 0.10 M) was added dropwise. 1H NMR spectroscopic analysis of the unpurified product indicated the formation of a 9:1 ratio of diastereomers. Purification by flash chromatography (Hexanes/Et2O, 50:50) provided 20b (0.35 g, 85%) as a white foam. Rf = 0.20 (Hexanes/Et2O, 50:50); [α]D25 +5.0 (c 1.5, CHCl3); C51H58O10SSi; MW = 891.1600 gmol-1; IR (neat, cm-1) νmax 3443, 2932, 1749, 1613, 1514, 1249; 1H NMR (500 MHz, CDCl3) δ (ppm) 7.76 – 7.66 (m, 4H), 7.47 – 7.36 (m, 7H), 7.34 – 7.24 (m, 6H), 7.25 – 7.19 (m, 2H), 6.87 (d, J = 8.8 Hz, 2H), 6.82 (d, J = 8.8 Hz, 2H), 5.16 (d, J = 12.1 Hz, 1H), 5.05 (d, J = 12.1 Hz, 1H), 4.83 (m, 2H), 4.79 (d, J = 10.0 Hz, 1H), 4.74 (d, J = 10.5 Hz, 1H), 4.65 (d, J = 10.0 Hz, 1H), 4.44 (d, J = 9.7 Hz, 1H), 4.17 (dd, J = 11.4, 5.1 Hz, 1H), 4.08 (s, 1H), 4.02 (dd, J = 11.4, 1.9 Hz, 1H), 3.81 (s, 3H), 3.78 (s, 3H), 3.68 (dd, J = 9.8, 8.8 Hz, 1H), 3.50 (d, J = 8.8 Hz, 1H), 3.39 (dd, J = 5.0, 1.7 Hz, 1H), 2.92 – 2.81 (m, 2H), 2.80 – 2.69 (m, 1H), 1.35 (t, J = 7.4 Hz, 3H), 1.04 (s, 9H); 13C{1H} NMR (126 MHz, CDCl3) δ (ppm) 169.7, 159.45, 159.43, 135.8, 135.7, 134.6, 132.85, 132.78, 130.5, 130.2, 130.1, 130.0, 129.95, 129.93, 128.9, 128.8, 128.5, 127.92, 127.87, 113.9, 113.8, 85.6, 85.4, 84.8, 81.4, 80.6, 78.0, 75.7, 75.5, 71.3, 68.4, 64.5, 61.5, 55.39, 55.36, 26.7, 24.2, 19.2, 15.3; HRMS calcd for C51H58O10SSiNa [M+Na+]: 913.3418, found 913.3427 (+1.6 ppm). Non-selective reduction of acetylenic α-ketoesters 18 and 19 (entries 4 and 5): To a solution of the corresponding acetylenic α-ketoester dissolved in anhydrous THF (0.1 M) at -78 °C, a solution of LiAlH(OtBu)3 (1.0 M in THF, 1.1 equiv) was added dropwise. After stirring for 15 min, methanol followed by a saturated solution of NH4Cl were added. The aqueous layer was extracted with Et2O and the combined organic layers were washed with brine, dried over MgSO4, filtered, and concentrated in vacuo. 1H NMR spectroscopic analysis of the unpurified product indicated the formation of a 1:1 ratio of diastereomers. Purification by flash chromatography (Hexanes/Et2O, 60:40) provided acetylenic α-hydroxyesters 20a,b or 21a,b as an inseparable mixture of diastereomers (94-97%). Compounds from Scheme 4: Ethyl 4-C-((1R)benzyloxycarbonyl-1-hydroxyprop-2-yn-3-yl)-6-O-(tertbutyldiphenylsilyl)-2,3-di-O-(p-methoxybenzyl)-4-O-

Page 10 of 20

trimethylsilyl-1-thio-β-D-galactopyranoside (21a). To a vigorously stirred solution of 20a (0.45 g, 0.51 mmol, 1.0 equiv) in anhydrous dichloromethane (5.1 mL, 0.10 M) at 40 °C, 2,6-lutidine (175 μL, 1.51 mmol, 3.00 equiv) and TMSOTf (228 μL, 1.26 mmol, 2.50 equiv) were added. The reaction vessel was sealed with a Teflon cap and kept at -20 °C for 16 h. Water (10 mL) was then slowly added, and the solution was diluted with dichloromethane (5 mL) and warmed to 25 °C. The organic layer was collected and washed with a HCl solution (1 M, 5 mL), a saturated solution of NaHCO3 (10 mL), followed by brine (10 mL). The organic layer was dried over MgSO4, filtered, and concentrated in vacuo. The crude viscous oil was then dissolved in dichloromethane (8 mL, 0.07 M) and methanol (1.0 mL, 0.49 M), and a solution of PPTS (0.10 M in methanol, 0.51 mL, 0.10 equiv) was added dropwise. After stirring for 2 h, a saturated solution of NaHCO3 (10 mL) was added. The aqueous layer was extracted with Et2O (2 x 10 mL) and the combined organic layers were washed with brine (20 mL), dried over MgSO4, filtered, and concentrated in vacuo. Purification by flash chromatography (Hexanes/Et2O, 50:50) provided 21a (0.42 g, 87%) as a clear oil. Rf = 0.35 (Hexanes/Et2O, 50:50); C54H66O10SSi2; MW = 963.3420 gmol-1; IR (neat, cm-1) νmax 3466, 2956, 1749, 1514, 1249; 1H NMR (500 MHz, CDCl3) δ (ppm) 7.69 (dd, J = 11.8, 6.5 Hz, 4H), 7.44 – 7.31 (m, 7H), 7.34 – 7.19 (m, 8H), 6.84 (dd, J = 15.4, 8.6 Hz, 4H), 5.23 (d, J = 12.0 Hz, 1H), 5.00 (d, J = 12.0 Hz, 1H), 4.75 (d, J = 10.4 Hz, 1H), 4.71 (dd, J = 10.3, 6.9 Hz, 3H), 4.63 (d, J = 10.0 Hz, 1H), 4.47 (d, J = 9.5 Hz, 1H), 4.04 (dd, J = 11.2, 2.0 Hz, 1H), 3.89 (dd, J = 11.3, 8.2 Hz, 1H), 3.80 (s, 3H), 3.80 (s, 3H), 3.54 – 3.44 (m, 2H), 3.42 (d, J = 9.1 Hz, 1H), 2.86 (dq, J = 12.9, 7.4 Hz, 1H), 2.81 – 2.68 (m, 2H), 1.36 (t, J = 7.4 Hz, 3H), 1.05 (s, 9H), -0.04 (s, 9H); 13C{1H} NMR (126 MHz, CDCl3) δ (ppm) 169.6, 159.4, 159.2, 135.83, 135.75, 134.5, 134.1, 133.7, 130.52, 130.50, 130.13, 130.09, 129.74, 129.71, 129.0, 128.82, 128.77, 127.762, 127.760, 113.9, 113.6, 86.9, 85.11, 85.08, 84.1, 82.1, 78.1, 76.2, 75.3, 72.6, 68.5, 64.1, 61.5, 55.42, 55.37, 26.9, 24.8, 19.4, 15.2, 2.0; HRMS calcd for C54H66O10SSi2Na [M+Na+]: 985.3813, found 985.3803 (-0.4 ppm). Ethyl 4-C-((1S)-benzyloxycarbonyl-1-hydroxyprop-2-yn-3yl)-6-O-(tert-butyldiphenylsilyl)-2,3-di-O-(pmethoxybenzyl)-4-O-trimethylsilyl-1-thio-β-Dgalactopyranoside (21b). Following a similar procedure as in 21a, to solution of 20b (0.48 g, 0.54 mmol, 1.0 equiv) in anhydrous dichloromethane (5.4 mL, 0.10 M), 2,6-lutidine (189 μL, 1.63 mmol, 3.00 equiv) and TMSOTf (246 μL, 1.35 mmol, 2.50 equiv) were added. The crude oil was then dissolved in dichloromethane (8 mL, 0.07 M) and methanol (1.1 mL, 0.49 M), and a solution of PPTS (0.10 M in methanol, 0.54 mL, 0.10 equiv) was added dropwise. Purification by flash chromatography (Hexanes/Et2O, 50:50) provided 21b (0.48 g, 92%) as a clear oil. Rf = 0.35 (Hexanes/Et2O, 50:50); C54H66O10SSi2; MW = 963.3420 gmol-1; IR (neat, cm-1) νmax 3466, 2956, 1749, 1514, 1249; 1H NMR (500 MHz, CDCl3) δ (ppm) 7.74 – 7.65 (m, 4H), 7.46 – 7.34 (m, 7H), 7.35 – 7.19 (m, 8H), 6.85 (d, J = 8.7 Hz, 2H), 6.81 (d, J = 8.6 Hz, 2H), 5.23 (d, J = 12.0 Hz, 1H), 4.96 (d, J = 12.0 Hz, 1H), 4.79 – 4.68 (m, 4H), 4.62 (d, J = 9.9 Hz, 1H), 4.46 (d, J = 9.6 Hz, 1H), 4.06 (dd, J = 11.2, 2.0 Hz, 1H), 3.88 (dd, J = 11.2, 8.1 Hz, 1H), 3.80 (s, 3H), 3.79 (s, 3H), 3.52 – 3.45 (m, 2H), 3.39 (d, J = 9.1 Hz, 1H), 2.91 – 2.81 (m, 1H),


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2.81 – 2.72 (m, 2H), 1.36 (t, J = 7.4 Hz, 3H), 1.06 (s, 9H), -0.02 (s, 9H); 13C{1H} NMR (126 MHz, CDCl3) δ (ppm) 169.5, 159.4, 159.2, 135.8, 135.7, 134.5, 134.1, 133.6, 130.51, 130.45, 130.11, 130.09, 129.74, 129.70, 129.0, 128.8, 128.7, 127.78, 127.75, 113.9, 113.6, 86.9, 85.1, 85.0, 84.0, 82.0, 78.1, 76.1, 75.3, 72.6, 68.5, 64.1, 61.5, 55.4, 55.3, 26.9, 24.7, 19.4, 15.2, 2.0; HRMS calcd for C54H66O10SSi2Na [M+Na+]: 985.3813, found 985.3800 (-0.8 ppm). Ethyl 4-O,4-C-((1R)-benzyloxycarbonylprop-2-en-1,3-diyl)6-O-(tert-butyldiphenylsilyl)- 2,3-di-O-(p-methoxybenzyl)-1thio-β-D-galactopyranoside (22a). To a solution of 20b (25 mg, 28 μmol, 1.0 equiv) in Et2O (0.9 mL, 0.03 M), 2,4,6triisopropylbenzenesulfonyl hydrazide (50 mg, 0.17 mmol, 6.0 equiv) was added. The reaction mixture was refluxed in an oil bath for 16 h. After cooling to 25 °C, a saturated solution of NaHCO3 (5 mL) was added to the reaction mixture, and the aqueous layer was extracted with Et2O (2 x 5 mL), washed with brine (10 mL), dried over MgSO4, filtered, and concentrated in vacuo. The crude viscous oil was then dissolved in dichloromethane (0.20 mL, 0.14 M) and pyridine (77 μL, 0.36 M) at 0 °C, methanesulfonyl chloride (3.00 μL, 38.8 μmol, 2.00 equiv) was added dropwise. The reaction mixture was warmed to 40 °C and stirred for 3 h before water (2 mL) was added, and the aqueous layer was extracted with dichloromethane (2 x 2 mL), washed with brine, dried over MgSO4, filtered, and concentrated in vacuo. 1H NMR spectroscopic analysis of the unpurified product indicated the formation of a 4:1 ratio of diastereomers. Purification by flash chromatography (Hexanes/Et2O, 50:50) provided a 6:1 diastereomeric ratio of 22a (18 mg, 72%) as a clear oil. Rf = 0.29 (Hexanes/Et2O, 50:50); C51H58O9SSi; MW = 875.3571 gmol-1; IR (neat, cm-1) νmax 3069, 2931, 1759, 1733, 1613, 1514, 1249; 1H NMR (500 MHz, CDCl3) δ (ppm) 7.67 – 7.60 (m, 4H), 7.44 – 7.33 (m, 11H), 7.33 – 7.27 (m, 2H), 7.12 (d, J = 8.7 Hz, 2H), 6.83 (dd, J = 8.7, 7.9 Hz, 4H), 5.86 (dd, J = 5.9, 1.8 Hz, 1H), 5.35 (dd, J = 2.7, 1.8 Hz, 1H), 5.33 (dd, J = 5.9, 2.8 Hz, 1H), 5.01 – 4.92 (m, 2H), 4.79 (d, J = 9.9 Hz, 1H), 4.65 (d, J = 10.5 Hz, 1H), 4.62 (d, J = 9.9 Hz, 1H), 4.43 (d, J = 9.7 Hz, 1H), 4.39 (d, J = 10.6 Hz, 1H), 4.03 (dd, J = 11.6, 6.7 Hz, 1H), 3.84 (dd, J = 11.6, 3.8 Hz, 1H), 3.794 (s, 3H), 3.790 (s, 3H), 3.71 (dd, J = 9.8, 9.1 Hz, 1H), 3.51 – 3.45 (m, 1H), 3.31 (d, J = 9.1 Hz, 1H), 2.86 – 2.77 (m, 1H), 2.77 – 2.67 (m, 1H), 1.31 (t, J = 7.4 Hz, 3H), 1.02 (s, 9H); 13C{1H} NMR (126 MHz, CDCl3) δ (ppm) 169.5, 159.4, 159.3, 135.80, 135.78, 134.1, 133.8, 130.7, 130.6, 130.1, 129.73, 129.70, 129.5, 128.8, 128.6, 128.39, 128.37, 128.32, 128.31, 127.77, 127.75, 113.9, 113.8, 94.7, 85.8, 85.0, 84.3, 81.3, 79.8, 75.6, 75.5, 66.7, 63.8, 55.43, 55.41, 26.9, 24.7, 19.3, 15.2; HRMS calcd for C51H58O9SSiNa [M+Na+]: 897.3469, found 897.3452 (-1.3 ppm). Ethyl 4-O,4-C-((1S)-benzyloxycarbonylprop-2-en-1,3-diyl)6-O-(tert-butyldiphenylsilyl)- 2,3-di-O-(p-methoxybenzyl)-1thio-β-D-galactopyranoside (22b). Following a similar procedure as in 22a, to a solution of 20a (60 mg, 67 μmol, 1.0 equiv) in Et2O (2.0 mL, 0.03 M), 2,4,6triisopropylbenzenesulfonyl hydrazide (0.12 g, 0.40 mmol, 6.0 equiv) was added. The crude oil was then dissolved in dichloromethane (0.67 mL, 0.10 M) and pyridine (0.19 mL, 0.35 M) and methanesulfonyl chloride (10 μL, 0.13 mmol, 2.0 equiv) was added dropwise. 1H NMR spectroscopic analysis of the unpurified product indicated the formation

of an 8:1 ratio of diastereomers. Purification by flash chromatography (Hexanes/Et2O, 50:50) provided an 8:1 diastereomeric ratio of 22a (50 mg, 76%) as a clear oil. Rf = 0.30 (Hexanes/Et2O, 50:50); C51H58O9SSi; MW = 875.3571 gmol-1; IR (neat, cm-1) νmax 3070, 2931, 1760, 1728, 1613, 1514, 1248; 1H NMR (500 MHz, CDCl3) δ (ppm) 7.66 – 7.59 (m, 4H), 7.50 – 7.31 (m, 5H), 7.25 – 7.18 (m, 8H), 7.10 (d, J = 8.6 Hz, 2H), 6.85 (d, J = 8.6 Hz, 2H), 6.80 (d, J = 8.6 Hz, 2H), 6.02 (dd, J = 6.0, 2.0 Hz, 1H), 5.40 (dd, J = 6.0, 2.4 Hz, 1H), 5.04 (t, J = 2.2 Hz, 1H), 4.83 (d, J = 12.4 Hz, 1H), 4.78 (d, J = 12.4 Hz, 1H), 4.57 (d, J = 9.9 Hz, 1H), 4.48 (d, J = 10.4 Hz, 1H), 4.44 (d, J = 9.8 Hz, 1H), 4.40 (d, J = 10.0 Hz, 1H), 4.37 (d, J = 10.4 Hz, 1H), 3.80 (s, 3H), 3.82 – 3.75 (m, 1H), 3.77 (s, 3H), 3.69 (dd, J = 10.4, 4.2 Hz, 1H), 3.66 (appt, J = 8.8 Hz, 1H), 3.54 (dd, J = 5.7, 4.8 Hz, 1H), 3.30 (d, J = 9.1 Hz, 1H), 2.79 (dq, J = 12.6, 7.4 Hz, 1H), 2.68 (dq, J = 12.6, 7.4 Hz, 1H), 1.29 (t, J = 7.4 Hz, 3H), 1.02 (s, 9H); 13C{1H} NMR (126 MHz, CDCl3) δ (ppm) 169.7, 159.4, 159.3, 135.8, 133.6, 133.4, 130.8, 130.5, 130.2, 130.0, 129.9, 129.8, 128.4, 128.3, 128.1, 128.05, 128.03, 127.83, 127.81, 113.9, 113.6, 94.4, 85.3, 84.9, 83.5, 81.2, 79.4, 75.3, 75.2, 66.6, 63.0, 55.43, 55.39, 27.0, 24.6, 19.3, 15.2; HRMS calcd for C51H58O9SSiNa [M+Na+]: 897.3469, found 897.3469 (+0.7 ppm). Ethyl 4-C-((1R,Z)-benzyloxycarbonyl-1-hydroxyprop-2-en3-yl)-6-O-(tert-butyldiphenylsilyl)-2,3-di-O-(pmethoxybenzyl)-4-O-trimethylsilyl-1-thio-β-Dgalactopyranoside (23a). To a solution of 21a (740 mg, 768 μmol, 1.00 equiv) in Et2O (15 mL, 0.050 M), 2,4,6triisopropylbenzenesulfonyl hydrazide (1.15 g, 3.84 mmol, 5.00 equiv) was added. The reaction mixture was refluxed for 16 h. After cooling to 25 °C, a saturated solution of NaHCO3 (15 mL) was added to the reaction mixture, and the aqueous layer was extracted with Et2O (2 x 15 mL), washed with brine (15 mL), dried over MgSO4, filtered, and concentrated in vacuo. Purification by flash chromatography (Hexanes/Et2O, 50:50) provided 23a (0.50 g, 67%) as a white foam. Rf = 0.17 (Hexanes/Et2O, 40:60); [α]D25 +2.6 (c 0.3, CHCl3); C54H68O10SSi2; MW = 965.3580 gmol-1; IR (neat, cm-1) νmax 3448, 2070, 2955, 1740, 1613, 1514, 1249; 1H NMR (500 MHz, CDCl3) δ (ppm) 7.69 (d, J = 6.5 Hz, 2H), 7.64 (d, J = 6.6 Hz, 2H), 7.42 – 7.24 (m, 13H), 7.18 (d, J = 8.6 Hz, 2H), 6.83 (d, J = 8.6 Hz, 2H), 6.79 (d, J = 8.7 Hz, 2H), 5.49 (dd, J = 12.6, 1.1 Hz, 1H), 5.36 (dd, J = 12.6, 9.0 Hz, 1H), 5.12 (d, J = 12.2 Hz, 1H), 5.14 – 5.08 (m, 1H), 5.08 (d, J = 12.2 Hz, 1H), 4.78 (d, J = 9.8 Hz, 1H), 4.75 (d, J = 10.8 Hz, 1H), 4.66 (d, J = 10.8 Hz, 1H), 4.62 (d, J = 9.8 Hz, 1H), 4.47 (d, J = 9.8 Hz, 1H), 3.91 (dd, J = 11.3, 2.7 Hz, 1H), 3.85 (dd, J = 11.3, 7.2 Hz, 1H), 3.81 (d, J = 9.0 Hz, 1H), 3.79 (s, 3H), 3.78 (s, 3H), 3.75 (dd, J = 7.7, 2.7 Hz, 1H), 3.59 (appt, J = 9.4 Hz, 1H), 2.89 – 2.65 (m, 3H), 1.32 (t, J = 7.4 Hz, 3H), 1.03 (s, 9H), 0.01 (s, 9H); 13C{1H} NMR (126 MHz, CDCl3) δ (ppm) 173.2, 159.5, 159.1, 138.5, 135.9, 135.8, 135.3, 134.1, 133.7, 130.9, 130.5, 130.1, 129.8, 129.69, 129.67, 128.74, 128.72, 128.66, 128.5, 127.73, 127.71, 113.9, 113.6, 85.7, 84.9, 83.8, 80.9, 79.4, 75.7, 75.1, 67.7, 67.1, 63.9, 55.43, 55.36, 27.0, 24.7, 19.4, 15.2, 2.9; HRMS calcd for C54H68O+ 10SSi2Na [M+Na ]: 987.3964, found 987.3948 (-1.8 ppm). 4-C-((1S,Z)-benzyloxycarbonyl-1-hydroxyprop-2-en-3-yl)6-O-(tert-butyldiphenylsilyl)-2,3-di-O-(p-methoxybenzyl)-4O-trimethylsilyl-1-thio-β-D-galactopyranoside (23b). Following a similar procedure as in 23a, to a solution of 21b



(423 mg, 439 μmol, 1.00 equiv) in Et2O (9 mL, 0.05 M), 2,4,6triisopropylbenzenesulfonyl hydrazide (655 mg, 2.20 mmol, 5.00 equiv) was added. Purification by flash chromatography (Hexanes/Et2O, 50:50) provided 23b (0.37 g, 87%) as a white foam. Rf = 0.21 (Hexanes/Et2O, 40:60); [α]D25 +35 (c 0.8, CHCl3); C54H68O10SSi2; MW = 965.3580 gmol-1; IR (neat, cm-1) νmax 2931, 1734, 1614, 1514, 1249; 1H NMR (500 MHz, CDCl3) δ (ppm) 7.69 (d, J = 6.5 Hz, 2H), 7.65 (d, J = 6.6 Hz, 2H), 7.45 – 7.26 (m, 9H), 7.24 (s, 4H), 7.15 (d, J = 8.6 Hz, 2H), 6.85 (d, J = 8.6 Hz, 2H), 6.78 (d, J = 8.6 Hz, 2H), 5.45 (dd, J = 12.4, 8.6 Hz, 1H), 5.29 (d, J = 12.3 Hz, 1H), 5.18 (dd, J = 8.9, 3.5 Hz, 1H), 5.11 (d, J = 12.1 Hz, 1H), 5.05 (d, J = 12.1 Hz, 1H), 4.81 (d, J = 9.8 Hz, 1H), 4.68 (d, J = 10.6 Hz, 1H), 4.62 (d, J = 9.8 Hz, 1H), 4.57 (d, J = 10.6 Hz, 1H), 4.49 (d, J = 9.6 Hz, 1H), 3.88 – 3.74 (m, 2H), 3.80 (s, 3H), 3.78 (s, 3H), 3.66 (dd, J = 7.0, 2.7 Hz, 1H), 3.61 (t, J = 9.3 Hz, 1H), 3.55 (d, J = 9.1 Hz, 1H), 3.06 (d, J = 3.8 Hz, 1H), 2.89 – 2.70 (m, 2H), 1.33 (t, J = 7.4 Hz, 3H), 1.02 (s, 9H), 0.03 (s, 9H); 13C{1H} NMR (126 MHz, CDCl3) δ (ppm) 173.0, 159.5, 159.3, 136.8, 135.8, 135.8, 135.3, 133.7, 133.5, 130.4, 130.2, 130.1, 130.0, 129.81, 129.77, 129.72, 128.7, 128.6, 127.79, 127.77, 127.6, 113.9, 113.6, 85.3, 84.9, 84.3, 81.3, 79.4, 75.9, 75.1, 67.4, 66.7, 63.8, 55.4, 55.3, 26.9, 25.1, 19.2, 15.3, 3.0; HRMS calcd for C54H68O10SSi2Na [M+Na+]: 987.3964, found 987.3960 (-0.4 ppm). Ethyl 4-C-((1R,Z)-benzyloxycarbonyl-1methanesulfonyloxyprop-2-en-3-yl)-6-O-(tertbutyldiphenylsilyl)-4-O-trimethylsilyl-1-thio-β-Dgalactopyranoside (24a). To a solution of 23a (250 mg, 259 mmol, 1.00 equiv) in anhydrous dichloromethane (2.6 mL, 0.10 M) at 0 °C, triethylamine (90.2 μL, 647 μmol, 2.50 equiv) and methanesulfonyl chloride (40.1 μL, 518 μmol, 2.00 equiv) were added dropwise. The reaction mixture was warmed to 25 °C and stirred for 30 min. before water (5 mL) was added, and the aqueous layer was extracted with dichloromethane (2 x 5 mL), washed with brine, dried over MgSO4, filtered, and concentrated in vacuo. The crude residue was dissolved in a 20:1 solution of dichloromethane and water (5.2 mL, 0.05 M) and DDQ (129 mg, 569 μmol, 2.20 equiv) was added. The reaction mixture was stirred for 30 min. before being refluxed for 30 min. After cooling to 25 °C, a saturated solution of NaHCO3 (10 mL) was added to the reaction mixture, and the aqueous layer was extracted with ethyl acetate (2 x 10 mL), washed with brine (10 mL), dried over MgSO4, filtered, and concentrated in vacuo. Purification by flash chromatography (Hexanes/EtOAc, 50:50) provided 24a (0.15 g, 72 %) as a clear oil. Rf = 0.4 (Hexanes/EtOAc, 50:50): [α]D25 -50 (c 1.1, CHCl3); C39H54O10S2Si2 MW = 803.1410 gmol-1; IR (neat, cm-1) νmax 3503, 2956, 1757, 1733, 1363; 1H NMR (500 MHz, CDCl3) δ (ppm) 7.66 (dd, J = 12.6, 6.5 Hz, 4H), 7.43 – 7.32 (m, 11H), 6.35 (d, J = 7.4 Hz, 1H), 5.50 – 5.44 (m, 2H), 5.24 (d, J = 12.0 Hz, 1H), 5.16 (d, J = 12.0 Hz, 1H), 4.07 (d, J = 9.7 Hz, 1H), 3.89 (dd, J = 11.2, 3.9 Hz, 1H), 3.80 (d, J = 8.8 Hz, 1H), 3.77 (dd, J = 11.3, 6.3 Hz, 1H), 3.60 (dd, J = 9.7, 8.9 Hz, 1H), 3.46 (dd, J = 6.2, 4.0 Hz, 1H), 2.95 (s, 3H), 2.73 – 2.65 (m, 2H), 1.29 (t, J = 7.5 Hz, 3H), 1.05 (s, 9H), 0.08 (s, 9H) (Labile protons were not observed due to exchange with deuterated solvent); 13C{1H} NMR (126 MHz, CDCl3) δ (ppm) 167.8, 137.1, 135.8, 135.7, 134.4, 133.6, 133.3, 129.9, 129.8, 129.04, 128.95, 128.87, 127.9, 127.8, 123.0, 86.0, 83.5, 80.4, 75.7, 74.4, 70.4, 68.7, 63.3, 39.0, 27.0, 24.7, 19.3, 15.5, 2.8; HRMS calcd for

Page 12 of 20

C39H54O10S2Si2Na [M+Na+]: 825.2589, found 825.2586 (-0.4 ppm). Ethyl 4-C-((1S,Z)-benzyloxycarbonyl-1methanesulfonyloxyprop-2-en-3-yl)-6-O-(tertbutyldiphenylsilyl)-4-O-trimethylsilyl-1-thio-β-Dgalactopyranoside (24b). Following a similar procedure as in 24a, to a solution of 23b (320 mg, 331 mmol, 1.00 equiv) in anhydrous dichloromethane (3.3 mL, 0.10 M), triethylamine (116 μL, 829 μmol, 2.50 equiv) and methanesulfonyl chloride (51.3 μL, 663 μmol, 2.00 equiv) were added dropwise. The crude residue was dissolved in a 20:1 solution of dichloromethane and water (6.5 mL, 0.05 M) and DDQ (163 mg, 717 μmol, 2.20 equiv) was added. Purification by flash chromatography (Hexanes/EtOAc, 50:50) provided 24b (0.19 g, 74%) as a clear oil. Rf = 0.23 (EtOAc/Hex 1:1); [α]D25 +23 (c 1.4, CHCl3); C39H54O10S2Si2; MW = 803.1410 gmol-1; IR (neat, cm-1) νmax 3505, 2931, 1751, 1360; 1H NMR (500 MHz, CDCl3) δ (ppm) 7.68 (dd, J = 14.9, 6.5 Hz, 4H), 7.47 – 7.34 (m, 7H), 7.31 – 7.24 (m, 2H), 7.22 (d, J = 7.7 Hz, 2H), 6.46 (d, J = 9.8 Hz, 1H), 5.50 (dd, J = 12.2, 9.8 Hz, 1H), 5.40 (d, J = 12.2 Hz, 1H), 5.10 (d, J = 12.1 Hz, 1H), 4.98 (d, J = 12.0 Hz, 1H), 4.42 (d, J = 9.2 Hz, 1H), 3.88 (dd, J = 11.6, 3.0 Hz, 1H), 3.81 (dd, J = 11.6, 7.0 Hz, 1H), 3.64 – 3.50 (m, 3H), 3.05 (s, 3H), 2.83 – 2.68 (m, 2H), 2.62 (s, 2H), 1.33 (t, J = 7.4 Hz, 3H), 1.05 (s, 9H), 0.07 (s, 9H); 13C{1H} NMR (126 MHz, CDCl3) δ (ppm) 167.4, 137.7, 135.82, 135.75, 134.7, 133.6, 133.4, 129.9, 129.8, 128.8, 128.7, 128.6, 127.9, 127.8, 123.4, 86.3, 84.3, 81.1, 77.2, 73.4, 70.8, 67.9, 63.6, 39.4, 26.9, 25.2, 19.3, 15.4, 3.0; HRMS calcd for C39H54O10S2Si2Na [M+Na+]: 825.2589, found 825.2586 (-0.4 ppm). Compounds in Table 2: Ethyl 3-O,4-C-((1S)benzyloxycarbonylprop-2-en-1,3-diyl)-6-O-(tertbutyldiphenylsilyl)-4-O-trimethylsilyl-1-thio-β-Dgalactopyranoside (25b). To a 1:1 mixture of 24a and 24b (4.00 g, 4.98 mmol, 1.00 equiv) in anhydrous toluene (16 mL, 0.20 M), diisopropylethylamine (2.60 mL, 14.9 mmol, 3.00 equiv) was added. The reaction mixture was warmed to 100 °C for 2 h. The dark brown solution was then cooled to room temperature and a saturated solution of NaHCO3 (20 mL) was added. The aqueous layer was extracted with ethyl acetate (2 x 20 mL), and the combined organic layers were washed with brine (40 mL), dried over MgSO4, filtered, and concentrated in vacuo. 1H NMR spectroscopic analysis of the unpurified product indicated the formation of a 13:1 ratio of diastereomers. Purification by flash chromatography (Hexanes/ Et2O, 50:50) provided 25b (2.3 g, 65%) as a clear oil. Note: 41 mg of 25a was recovered as an inseparable mixture with an unknown decomposition product. Rf = 0.31 (Hexanes/ Et2O, 50:50); [α]D25 -51 (c 0.3, CHCl3); C38H50O7SSi2; MW = 707.0410 gmol-1; IR (neat, cm-1) νmax 3483, 2931, 1749, 1251; 1H NMR (500 MHz, CDCl3) δ (ppm) 7.65 (ddd, J = 6.8, 3.4, 1.7 Hz, 4H), 7.44 – 7.33 (m, 11H), 6.33 (dd, J = 10.2, 2.7 Hz, 1H), 6.08 (dd, J = 10.2, 3.4 Hz, 1H), 5.27 (d, J = 12.2 Hz, 1H), 5.20 (d, J = 12.2 Hz, 1H), 4.88 (t, J = 3.1 Hz, 1H), 4.29 (d, J = 9.2 Hz, 1H), 3.97 (dd, J = 10.9, 6.0 Hz, 1H), 3.81 (td, J = 9.4, 1.7 Hz, 1H), 3.73 (dd, J = 10.9, 4.9 Hz, 1H), 3.65 (d, J = 9.6 Hz, 1H), 3.33 (dd, J = 6.0, 4.9 Hz, 1H), 2.76 – 2.61 (m, 2H), 2.50 (d, J = 1.8 Hz, 1H), 1.27 (t, J = 7.5 Hz, 3H), 1.06 (s, 9H), 0.02 (s, 9H); 13C{1H} NMR (126 MHz, CDCl3) δ (ppm) 169.5, 135.79, 135.76, 135.3, 133.4,


Page 13 of 20 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


133.3, 129.93, 129.91, 129.1, 128.8, 128.7, 128.6, 128.5, 127.88, 127.86, 86.2, 81.1, 80.7, 73.4, 68.8, 67.5, 67.4, 63.0, 27.0, 23.9, 19.3, 15.4, 2.2; HRMS calcd for C38H50O7SSi2Na [M+Na+]: 729. 2713, found 729.2717 (-0.1 ppm). Ethyl 4-O,4-C-((1R)-benzyloxycarbonylprop-2-en-1,3-diyl)6-O-(tert-butyldiphenylsilyl)-3-O-trimethylsilyl-1-thio-β-Dgalactopyranoside (26a) and Ethyl 4-O,4-C-((1S)benzyloxycarbonylprop-2-en-1,3-diyl)-6-O-(tertbutyldiphenylsilyl)-3-O-trimethylsilyl-1-thio-β-Dgalactopyranoside (26b). To a solution of 24a (62.0 mg, 77.2 μmol, 1.00 equiv) in acetonitrile (0.77 mL, 0.10 M), diisopropylethylamine (404 μL, 232 μmol, 3.00 equiv) was added. The reaction mixture was refluxed for 2 h. The dark brown solution was then cooled to room temperature and water (2 mL) was added. The aqueous layer was extracted with Et2O (2 x 2 mL), and the combined organic layers were washed with brine (4 mL), dried over MgSO4, filtered, and concentrated in vacuo. 1H NMR spectroscopic analysis of the unpurified product indicated the formation of a 3.4:1 ratio of inseparable diastereomers. Purification by flash chromatography (Hexanes/EtOAc, 70:30) provided 26a and 26b as a 3.2:1 mixture of diastereomers (46 mg, 84%) as a clear oil. Rf = 0.30 (Hexanes/EtOAc 60:40); C38H50O7SSi2; MW = 707.0410 gmol-1; IR (neat, cm-1) νmax 3532, 3070, 2957, 1760, 1731, 1428, 1249; HRMS calcd for C35H42O7SSiNa [M–TMS+Na+]: 657.2318, found 657.2303 (1.5 ppm). 26a: 1H NMR (500 MHz, CDCl3) δ (ppm) 7.69 – 7.60 (m, 4H), 7.48 – 7.31 (m, 7H), 7.27 (d, J = 1.9 Hz, 3H), 7.24 – 7.18 (m, 1H), 5.90 (dd, J = 6.0, 1.6 Hz, 1H), 5.35 (dd, J = 6.0, 2.8 Hz, 1H), 5.27 (dd, J = 2.8, 1.7 Hz, 1H), 5.00 (d, J = 12.2 Hz, 1H), 4.95 (d, J = 12.2 Hz, 1H), 4.30 (d, J = 9.8 Hz, 1H), 4.04 (dd, J = 11.6, 6.6 Hz, 1H), 3.88 (dd, J = 11.6, 3.7 Hz, 1H), 3.71 – 3.61 (m, 1H), 3.58 (dd, J = 6.6, 3.8 Hz, 1H), 3.43 (d, J = 8.7 Hz, 1H), 2.83 – 2.64 (m, 2H), 2.24 (d, J = 2.2 Hz, 1H), 1.31 (t, J = 7.4 Hz, 3H), 1.02 (s, 9H), 0.07 (s, 9H); 13C{1H} NMR (125 MHz, CDCl3) δ (ppm) 169.5, 135.83, 135.78, 134.1, 133.8, 129.86, 129.69, 129.4, 128.6, 128.5, 128.36, 128.33, 127.82, 127.74, 127.73, 94.7, 86.04, 85.98, 81.5, 78.1, 71.2, 66.6, 64.0, 26.9, 24.1, 19.3, 15.5, 0.6; 26b: 1H NMR (500 MHz, CDCl3) δ (ppm) 7.69 – 7.61 (m, 4H), 7.48 – 7.32 (m, 7H), 7.27 (dd, J = 2.8, 2.2 Hz, 3H), 7.24 – 7.18 (m, 1H), 6.00 (dd, J = 6.1, 1.9 Hz, 1H), 5.41 (dd, J = 6.1, 2.5 Hz, 1H), 5.17 (d, J = 12.4 Hz, 1H), 5.05 (d, J = 12.4 Hz, 1H), 5.01 (t, J = 2.2 Hz, 1H), 4.35 (d, J = 9.8 Hz, 1H), 3.80 (dd, J = 10.9, 5.7 Hz, 1H), 3.79 – 3.72 (m, 1H), 3.75 – 3.67 (m, 1H), 3.66 – 3.63 (m, 1H), 3.46 (d, J = 8.8 Hz, 1H), 2.85 – 2.64 (m, 2H), 2.20 (d, J = 2.3 Hz, 1H), 1.29 (t, J = 7.4 Hz, 3H), 1.03 (s, 9H), 0.01 (s, 9H); 13C{1H} NMR (126 MHz, CDCl3) δ (ppm) 169.3, 135.8, 135.7, 133.6, 133.4, 129.86, 129.82, 129.4, 128.7, 128.6, 128.5, 128.4, 128.3, 127.82, 127.80, 94.4, 85.9, 85.4, 81.6, 78.1, 70.9, 66.5, 63.2, 26.9, 24.1, 19.3, 15.4, 0.6. Ethyl 3-O,4-C-(benzyloxycarbonylprop-1-en-1,3-diyl)-6-O(tert-butyldiphenylsilyl)-4-O-trimethylsilyl-1-thio-β-Dgalactopyranoside (27). To a 1:1 mixture of 24a and 24b (30 mg, 18.7 μmol, 1.00 equiv) in anhydrous toluene (0.37 mL, 0.10 M), diisopropylethylamine (19.5 μL, 112 μmol, 3.00 equiv) was added. The reaction mixture was warmed to 100 °C for 16 h. The dark brown solution was then cooled to room temperature and a saturated solution of NaHCO3 (2 mL) was added. The aqueous layer was extracted with ethyl

acetate (2 x 2 mL), and the combined organic layers were washed with brine , dried over MgSO4, filtered, and concentrated in vacuo. Purification by flash chromatography (Hexanes/Et2O, 50:50) provided 27 (0.17 g, 64%) as a clear oil. Rf = 0.18 (Hexanes/Et2O, 50:50); [α]D25 +28 (c 0.9, CHCl3); C38H50O7SSi2; MW = 707.0410 gmol-1; IR (neat, cm-1) νmax 3410, 2931, 1724, 1652, 1428, 1252; 1H NMR (500 MHz, CDCl3) δ (ppm) 7.71 – 7.59 (m, 4H), 7.52 – 7.30 (m, 11H), 6.04 (dd, J = 5.0, 3.0 Hz, 1H), 5.28 (d, J = 12.4 Hz, 1H), 5.22 (d, J = 12.3 Hz, 1H), 4.33 (d, J = 9.6 Hz, 1H), 3.93 – 3.82 (m, 2H), 3.78 (dd, J = 11.0, 5.8 Hz, 1H), 3.47 (d, J = 9.1 Hz, 1H), 3.26 (t, J = 5.6 Hz, 1H), 2.84 (d, J = 1.9 Hz, 1H), 2.82 – 2.61 (m, 2H), 2.26 – 2.09 (m, 2H), 1.29 (t, J = 7.4 Hz, 3H), 1.06 (s, 9H), -0.04 (s, 9H); 13C{1H} NMR (126 MHz, CDCl3) δ (ppm) 162.0, 143.9, 135.81, 135.76, 133.4, 133.2, 130.0, 129.97, 128.7, 128.4, 128.3, 127.91, 127.903, 127.895, 110.1, 85.4, 83.0, 82.6, 70.6, 67.8, 66.9, 62.9, 31.2, 27.0, 23.6, 19.3, 15.3, 2.3; HRMS calcd for C38H50O7SSi2Na [M+Na+]: 729.2713, found 729.2724 (+2.1 ppm). Compounds in Scheme 6: Ethyl 2-O-benzoyl-3-O,4-C((1R)-benzyloxycarbonylprop-2-en-1,3-diyl)-6-O-(tertbutyldiphenylsilyl)-4-O-trimethylsilyl-1-thio-β-Dgalactopyranoside (30a). To a crude mixture of 25a (41 mg, 58 μmol, 50.0% purity, 1.0 equiv) in dichloromethane (0.28 mL, 0.10 M), pyridine (6.9 μL, 85 μmol, 3.0 equiv) and benzoyl chloride (4.9 μL, 424 μmol, 1.5 equiv) were added. After stirring for 16 h at 25 °C, a saturated solution of NaHCO3 (2 mL) was added. The aqueous layer was extracted with Et2O (2 x 2 mL), and the combined organic layers were washed with brine (4 mL), dried over MgSO4, filtered, and concentrated in vacuo. Purification by flash chromatography (Hexanes/Et2O, 70:30) provided 30a (17 mg, 72%) as a white foam. Rf = 0.33 (Hexanes/Et2O, 70:30); [α]D25 +11 (c 0.3, CHCl3); C45H54O8SSi2 MW = 811.1490 gmol1; IR (neat, cm-1) ν max 3049, 2957, 1765, 1731, 1452, 1267; 1H NMR (500 MHz, CDCl ) δ (ppm) 8.03 (dd, J = 8.3, 1.4 Hz, 3 2H), 7.75 – 7.64 (m, 4H), 7.62 – 7.51 (m, 1H), 7.48 – 7.35 (m, 9H), 7.30 (apps, 4H), 6.31 (dd, J = 10.3, 2.8 Hz, 1H), 6.10 (dd, J = 10.3, 1.8 Hz, 1H), 5.62 (t, J = 9.8 Hz, 1H), 5.15 (s, 2H), 4.83 (t, J = 2.4 Hz, 1H), 4.51 (d, J = 9.5 Hz, 1H), 4.03 (dd, J = 10.8, 6.3 Hz, 1H), 3.78 (dd, J = 10.8, 4.7 Hz, 1H), 3.62 (d, J = 10.0 Hz, 1H), 3.48 (dd, J = 6.3, 4.7 Hz, 1H), 2.76 (dq, J = 12.3, 7.4 Hz, 1H), 2.67 (dq, J = 12.3, 7.5 Hz, 1H), 1.21 (t, J = 7.5 Hz, 3H), 1.07 (s, 9H), 0.03 (s, 9H); 13C{1H} NMR (126 MHz, CDCl3) δ (ppm) 167.9, 165.4, 135.8, 135.7, 135.3, 133.5, 133.2, 133.0, 130.5, 130.0, 129.9, 129.4, 128.66, 128.64, 128.62, 128.47, 128.45, 128.41, 127.91, 127.89, 83.3, 81.6, 81.5, 76.0, 69.8, 68.3, 67.1, 62.9, 27.0, 22.9, 19.3, 15.0, 2.4; HRMS calcd for C45H54O8SSi2Na [M+Na+]: 833.2976, found 833.2984 (+1.7 ppm). Ethyl 2-O-benzoyl-3-O,4-C-((1S)-benzyloxycarbonylprop2-en-1,3-diyl)-6-O-(tert-butyldiphenylsilyl)-4-Otrimethylsilyl-1-thio-β-D-galactopyranoside (30b). Following a similar procedure as in 30a, to a solution of 25b (280 mg, 396 μmol, 1.00 equiv) in dichloromethane (4.0 mL, 0.10 M), pyridine (96 μL, 1.2 mmol, 3.0 equiv) and benzoyl chloride (69 μL, 0.59 mmol, 1.5 equiv) were added. Purification by flash chromatography (Hexanes/Et2O, 70:30) provided 30b (0.30 g, 93%) as a white foam. Rf = 0.40 (Hexanes/Et2O, 70:30); [α]D25 -58 (c 0.8, CHCl3); C45H54O8SSi2 MW = 811.1490 gmol-1; IR (neat, cm-1) νmax



3071, 2958, 1754, 1726, 1552, 1339; 1H NMR (500 MHz, CDCl3) δ (ppm) 8.20 – 8.07 (m, 2H), 7.75 – 7.62 (m, 4H), 7.58 – 7.51 (m, 1H), 7.55 – 7.35 (m, 8H), 7.35 – 7.25 (m, 3H), 7.28 – 7.23 (m, 2H), 6.40 (dd, J = 10.3, 2.8 Hz, 1H), 6.07 (dd, J = 10.3, 3.5 Hz, 1H), 5.54 (t, J = 9.8 Hz, 1H), 5.15 (d, J = 2.1 Hz, 2H), 4.83 (t, J = 3.1 Hz, 1H), 4.53 (d, J = 9.5 Hz, 1H), 4.05 (d, J = 10.2 Hz, 1H), 4.03 (d, J = 10.9 Hz, 1H), 3.79 (dd, J = 10.9, 4.8 Hz, 1H), 3.45 (dd, J = 6.1, 4.8 Hz, 1H), 2.76 (dq, J = 12.4, 7.5 Hz, 1H), 2.68 (dq, J = 12.4, 7.4 Hz, 1H), 1.22 (t, J = 7.5 Hz, 3H), 1.08 (s, 9H), 0.08 (s, 9H); 13C{1H} NMR (126 MHz, CDCl3) δ (ppm) 169.3, 165.9, 135.81, 135.76, 135.4, 133.5, 133.2, 132.9, 130.5, 130.2, 129.95, 129.93, 128.82, 128.80, 128.75, 128.6, 128.4, 128.3, 127.90, 127.89, 83.2, 81.0, 78.8, 73.3, 69.2, 68.5, 67.0, 63.0, 27.0, 23.1, 19.3, 15.0, 2.2; HRMS calcd for C45H54O8SSi2Na [M+Na+]: 833.2976, found 833.2971 (-0.6 ppm). Ethyl 2-O-benzoyl-3-O,4-C-(benzyloxycarbonylprop-1-en1,3-diyl)-1-thio-β-D-galactopyranoside (31). To a solution of 30b (22.0 mg, 27.1 μmol, 1.00 equiv) in anhydrous THF (0.3 mL, 0.09 M), TBAF (81 μL, 1.0 M in THF, 3.0 equiv) was added dropwise. The reaction mixture was stirred for 1 h before being diluted with EtOAc (2 mL) and a saturated solution of NH4Cl (2 mL) was added. The aqueous layer was extracted with EtOAc (2 x 2 mL), and the organic layers were combined, washed with brine (5 mL), dried over MgSO4, filtered and concentrated in vacuo. Purification by flash chromatography (Hexanes/EtOAc, 20:80) provided 31 (11 mg, 81%) as a clear oil. Rf = 0.41 (Hexanes/EtOAc, 10:90); [α]D25 +29 (c 0.3, CHCl3); C26H28O8S; MW = 500.5620 gmol-1; IR (neat, cm-1) νmax 3475, 3065, 2963, 1724, 1452, 1268;1H NMR (500 MHz, CDCl3) δ (ppm) 8.11 – 8.01 (m, 2H), 7.62 – 7.55 (m, 1H), 7.48 – 7.39 (m, 2H), 7.25 – 7.11 (m, 5H), 6.14 (dd, J = 5.1, 2.8 Hz, 1H), 5.66 (dd, J = 10.1, 9.4 Hz, 1H), 5.19 (d, J = 12.7 Hz, 1H), 5.05 (d, J = 12.6 Hz, 1H), 4.70 (d, J = 10.1 Hz, 1H), 4.06 (dd, J = 12.3, 6.1 Hz, 1H), 3.94 (dd, J = 12.4, 3.0 Hz, 1H), 3.89 (dd, J = 9.4, 1.4 Hz, 1H), 3.45 (dd, J = 6.1, 3.0 Hz, 1H), 2.87 – 2.67 (m, 2H), 2.32 (ddd, J = 18.7, 2.9, 1.1 Hz, 1H), 2.25 (ddd, J = 18.7, 5.1, 1.6 Hz, 1H), 1.86 (s, 2H), 1.27 (t, J = 7.4 Hz, 3H); 13C{1H} NMR (126 MHz, CDCl3) δ (ppm) 165.4, 161.6, 143.8, 135.5, 133.3, 130.1, 130.0, 129.9, 128.5, 128.1, 127.8, 108.9, 83.9, 81.4, 79.9, 68.8, 68.2, 66.7, 61.1, 31.6, 24.1, 15.0; HRMS calcd for C26H28O8SNa [M+Na+]: 523.1403, found 523.1396 (-0.1 ppm). Ethyl 2-O-benzoyl-3-O,4-C-((1R)-benzyloxycarbonylprop2-en-1,3-diyl)-1-thio-β-D-galactopyranoside (32a). To a solution of 30a (35.0 mg, 43.1 μmol, 1.00 equiv) in anhydrous THF (0.14 mL, 0.33 M), triethylamine trihydrofluoride (129 μL, 863 μmol, 20.0 equiv) was added. The reaction mixture was stirred for 3 h before being diluted with EtOAc (2 mL) and a saturated solution of NH4Cl (2 mL) was added. The aqueous layer was extracted with EtOAc (2 x 2 mL), and the organic layers were combined, washed with brine (5 mL), dried over MgSO4, filtered and concentrated in vacuo. Purification by flash chromatography (Hexanes/EtOAc, 20:80) provided 32a (15 mg, 69%) as a white foam. Rf = 0.45 (Hexanes/EtOAc, 10:90); [α]D25 +90 (c 0.2, CHCl3); C26H28O8S; MW = 500.5620 gmol-1; IR (neat, cm-1) νmax 3467, 3064, 2929, 1723, 1452, 1266; 1H NMR (500 MHz, CDCl3) δ (ppm) 8.12 – 8.02 (m, 2H), 7.57 (t, J = 7.4 Hz, 1H), 7.50 – 7.41 (m, 2H), 7.35 – 7.30 (m, 5H), 6.25 (dd, J = 10.1, 2.4 Hz, 1H), 5.99 (dd, J = 10.1, 2.4

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Hz, 1H), 5.64 (t, J = 9.7 Hz, 1H), 5.18 (s, 2H), 4.92 (td, J = 2.4, 0.7 Hz, 1H), 4.62 (d, J = 9.8 Hz, 1H), 4.08 (dd, J = 12.2, 6.7 Hz, 1H), 3.95 (dd, J = 12.2, 3.2 Hz, 1H), 3.78 (d, J = 9.6 Hz, 1H), 3.56 (dd, J = 6.7, 3.2 Hz, 1H), 2.88 – 2.67 (m, 2H), 1.63 (s, 2H), 1.26 (t, J = 7.5 Hz, 3H); 13C{1H} NMR (126 MHz, CDCl3) δ (ppm) 168.8, 165.4, 135.0, 133.2, 130.2, 130.1, 129.8, 128.83, 128.75, 128.53, 128.49, 128.42, 83.8, 79.8, 79.7, 75.5, 68.7, 67.8, 67.2, 60.7, 23.7, 15.0; HRMS calcd for C26H28O8SNa [M+Na+]: 523.1403, found 523.1399 (+0.4 ppm). Ethyl 2-O-benzoyl-3-O,4-C-((1S)-benzyloxycarbonylprop2-en-1,3-diyl)-1-thio-β-D-galactopyranoside (32b). Following a similar procedure as in 32a, to a solution of 30b (39.0 mg, 48.1 μmol, 1.00 equiv) in anhydrous THF (0.14 mL, 0.33 M), triethylamine trihydrofluoride (157 μL, 962 μmol, 20.0 equiv) was added. Purification by flash chromatography (Hexanes/EtOAc, 20:80) provided 32b (20 mg, 83%) as a white foam. Rf = 0.43 (Hexanes/EtOAc, 10:90); [α]D25 -124 (c 1.6, CHCl3); C26H28O8S; MW = 500.5620 gmol-1; IR (neat, cm-1) νmax 3468, 3064, 2967, 1749, 1721, 1452, 1267; 1H NMR (500 MHz, CDCl3) δ (ppm) 8.20 – 8.01 (m, 2H), 7.69 – 7.50 (m, 1H), 7.49 – 7.38 (m, 2H), 7.35 – 7.28 (m, 3H), 7.26 – 7.18 (m, 2H), 6.18 (dd, J = 10.2, 2.3 Hz, 1H), 6.13 (dd, J = 10.2, 3.2 Hz, 1H), 5.61 (t, J = 9.7 Hz, 1H), 5.13 (d, J = 12.2 Hz, 1H), 5.09 (d, J = 12.2 Hz, 1H), 4.91 (dd, J = 3.2, 2.3 Hz, 1H), 4.67 (d, J = 9.7 Hz, 1H), 4.17 (d, J = 9.7 Hz, 1H), 4.06 (dd, J = 12.2, 6.2 Hz, 1H), 3.96 (dd, J = 12.2, 3.2 Hz, 1H), 3.52 (dd, J = 6.3, 3.2 Hz, 1H), 2.87 – 2.68 (m, 2H), 2.36 (s, 2H), 1.26 (t, J = 7.4 Hz, 3H); 13C{1H} NMR (126 MHz, CDCl3) δ (ppm) 168.8, 165.9, 135.2, 133.1, 130.22, 130.20, 129.1, 128.8, 128.7, 128.5, 128.4, 128.2, 84.0, 79.5, 78.4, 73.2, 68.7, 67.2, 66.7, 60.8, 24.0, 15.1; HRMS calcd for C26H28O8SNa [M+Na+]: 523.1403, found 523.1395 (-0.4 ppm). Ethyl 2-O-benzoyl-3-O,4-C-((1R)-carboxyprop-1,3-diyl)-1thio-β-D-galactopyranoside (5a). To a solution of 32a (11.0 mg, 22.0 μmol, 1.00 equiv) in THF (1.8 mL, 0.01 M), palladium hydroxide (20 wt. %) on carbon (10.8 mg, 15.4 μmol, 0.70 equiv) was added. The reaction mixture was degassed and flushed with a hydrogen filled balloon. After stirring at 25 °C under a standard hydrogen atmosphere for 16 h, the reaction mixture was filtered through Celite, washed with methanol, and concentrated in vacuo. Purification by reverse phase C18 (H2O/MeOH, 60:40) provided 5a (6.5 mg, 72%) as a clear film. [α]D25 +35 (c 0.1, MeOH); C19H24O8S; MW = 412.4530 gmol-1; IR (neat, cm-1) νmax 3360, 2934, 1715, 1604, 1424, 1277; 1H NMR (500 MHz, CD3OD) δ (ppm) 8.00 (dd, J = 8.3, 1.4 Hz, 2H), 7.59 (t, J = 7.5 Hz, 1H), 7.50 – 7.43 (m, 2H), 5.42 (t, J = 9.7 Hz, 1H), 4.71 (d, J = 9.9 Hz, 1H), 3.89 (dd, J = 11.2, 3.6 Hz, 1H), 3.85 – 3.75 (m, 2H), 3.68 (d, J = 9.6 Hz, 1H), 3.51 (dd, J = 6.6, 3.5 Hz, 1H), 2.81 (dq, J = 12.4, 7.5 Hz, 1H), 2.73 (dq, J = 12.6, 7.5 Hz, 1H), 1.94 – 1.79 (m, 3H), 1.65 (td, J = 13.0, 5.5 Hz, 1H), 1.23 (t, J = 7.4 Hz, 3H) (Labile protons were not observed due to exchange with deuterated solvent); 13C{1H} NMR (126 MHz, CD3OD) δ (ppm) 179.2, 167.5, 134.2, 131.5, 130.8, 129.4, 84.9, 83.7, 82.5, 81.1, 70.9, 70.5, 61.3, 32.1, 25.5, 24.7, 15.3; HRMS calcd for C19H24O8SNa [M+Na+]: 435.1090, found: 435.1081 (-0.7 ppm). Ethyl 2-O-benzoyl-3-O,4-C-((1S)-carboxyprop-1,3-diyl)-1thio-β-D-galactopyranoside (5b). Following a similar procedure as in 5a, to a solution of 32b (22.0 mg, 43.9 μmol,


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1.00 equiv) in THF (0.9 mL, 0.05 M), palladium hydroxide (20 wt. %) on carbon (21.6 mg, 30.7 μmol, 0.70 equiv) was added. Purification by reverse phase C18 (H2O/MeOH, 60:40) provided 5b (16 mg, 88%) as a clear film. [α]D25 +11 (c 0.3, MeOH); C19H24O8S; MW = 412.4530 gmol-1; IR (neat, cm-1) νmax 3375, 3070, 2930, 1712, 1592, 1401, 1275; 1H NMR (500 MHz, CD3OD) δ (ppm) 8.12 – 8.05 (m, 2H), 7.62 – 7.53 (m, 1H), 7.50 – 7.42 (m, 2H), 5.37 (t, J = 9.8 Hz, 1H), 4.68 (d, J = 9.9 Hz, 1H), 4.34 (d, J = 9.7 Hz, 1H), 4.24 – 4.18 (m, 1H), 3.88 – 3.73 (m, 2H), 3.42 (dd, J = 6.2, 3.2 Hz, 1H), 2.85 – 2.66 (m, 2H), 2.30 – 2.19 (m, 1H), 2.13 – 2.05 (m, 1H), 1.71 – 1.58 (m, 2H), 1.22 (t, J = 7.4 Hz, 3H) (Labile protons were not observed due to exchange with deuterated solvent); 13C{1H} NMR (126 MHz, CD OD) δ (ppm) 178.8, 168.0, 3 133.9, 132.1, 131.0, 129.3, 85.4, 83.8, 77.9, 76.0, 71.2, 70.9, 61.4, 29.2, 24.9, 23.1, 15.3; HRMS calcd for C19H24O8SNa [M+Na+]: 435.1090, found 435.1083 (-0.3 ppm). Compounds from Scheme 7: (2R,3R)-2-O-(2-O-benzoyl3-O,4-C-((1S)-benzyloxycarbonylprop-2-en-1,3-diyl)-6-O(tert-butyldiphenylsilyl)-4-O-trimethylsilyl-β-Dgalactopyranosyl)-3-O-(2,3,4-tri-O-benzyl-α-Lfucopyranosyl)-tartaric acid diisopropyl ester (34). To a stirring solution of 30b (80 mg, 99 μmol, 1.0 equiv) and (2R,3R)-3-(2,3,4-tri-O-benzyl-α-L-fucopyranosyl)-tartaric acid diisopropyl ester 33 (128 mg, 197 μmol, 2.00 equiv) in anhydrous THF (2 mL, 0.05 M), activated 3Å molecular sieves (80 mg) were added. The reaction mixture was stirred at 25 °C for 30 min. before being cooled to -35 °C and N-iodosuccinimide (66.6 mg, 296 μmol, 3.00 equiv) and TMSOTf (3.6 μL, 20 μmol, 0.20 equiv) were added sequentially. The reaction mixture was stirred for 2 h at -35 °C and then filtered using Et2O and a saturated solution of Na2S2O3 (~1 mL) was added dropwise to the dark brown reaction mixture until it clarified. After warming to room temperature, a saturated solution of NaHCO3 (4 mL) was added. The aqueous layer was extracted with Et2O (2 x 5 mL) and the combined organic layers were washed with brine (10 mL), dried over MgSO4, filtered and concentrated in vacuo. Purification by flash chromatography (Hexanes/Et2O, 50:50) provided 34 (0.12 g, 87%) as a paleyellow oil. Rf = 0.32 (Hexanes/Et2O, 5:50); [α]D25 -80 (c 2.7, CHCl3); C80H94O18Si2; MW = 1399.7840 gmol-1; IR (neat, cm1) ν 1 max 3065, 2933, 1729, 1454, 1362, 1269; H NMR (500 MHz, CDCl3) δ (ppm) 8.25 – 7.86 (m, 2H), 7.79 – 7.60 (m, 4H), 7.48 – 7.23 (m, 25H), 7.28 – 7.17 (m, 4H), 6.37 (dd, J = 10.3, 2.7 Hz, 1H), 6.02 (dd, J = 10.2, 3.4 Hz, 1H), 5.44 (dd, J = 10.5, 7.6 Hz, 1H), 5.10 (d, J = 12.2 Hz, 1H), 5.05 (d, J = 12.1 Hz, 1H), 4.89 (d, J = 11.5 Hz, 1H), 4.85 (d, J = 3.5 Hz, 1H), 4.82 (d, J = 6.3 Hz, 1H), 4.81 – 4.77 (m, 2H), 4.76 (d, J = 5.4 Hz, 1H), 4.73 (s, 1H), 4.71 – 4.56 (m, 3H), 4.55 (d, J = 11.6 Hz, 1H), 4.49 (d, J = 5.4 Hz, 1H), 4.38 (d, J = 5.4 Hz, 1H), 4.02 (q, J = 6.5 Hz, 1H), 3.99 (dd, J = 10.7, 6.5 Hz, 1H), 3.92 (dd, J = 10.2, 2.6 Hz, 1H), 3.86 (dd, J = 10.2, 3.5 Hz, 1H), 3.85 (d, J = 10.4 Hz, 1H), 3.67 (dd, J = 10.7, 4.4 Hz, 1H), 3.51 (dd, J = 2.8, 1.3 Hz, 1H), 3.27 (dd, J = 6.6, 4.4 Hz, 1H), 1.13 (d, J = 6.3 Hz, 3H), 1.08 (s, 9H), 1.11 – 1.04 (m, 6H), 1.03 (d, J = 6.2 Hz, 3H), 0.94 (d, J = 6.4 Hz, 3H), 0.07 (s, 9H); 13C{1H} NMR (126 MHz, CDCl3) δ (ppm) 169.2, 168.3, 168.2, 165.8, 139.22, 139.19, 139.0, 135.73, 135.70, 135.4, 133.3, 133.0, 132.6, 130.9, 130.2, 130.0, 129.9, 129.1, 128.7, 128.7, 128.4, 128.38, 128.35, 128.34, 128.29, 128.27, 128.22, 128.0, 127.9, 127.89, 127.56, 127.53, 127.4, 127.3, 100.9, 99.8, 79.4, 78.2,

78.0, 77.9, 77.7, 77.6, 77.4, 75.9, 74.8, 73.3, 73.2, 72.5, 70.5, 69.1, 68.8, 67.4, 66.9, 62.8, 27.1, 21.8, 21.71, 21.66, 21.6, 19.3, 16.6, 2.2; HRMS calcd for C80H94O18Si2Na [M+Na+]: 1421.5876, found 1421.5832 (-2.7 ppm). (2R,3R)-2-O-(2-O-benzoyl-3-O,4-C-((1S)benzyloxycarbonylprop-2-en-1,3-diyl)-β-Dgalactopyranosyl)-3-O-(2,3,4-tri-O-benzyl-α-Lfucopyranosyl)-tartaric acid diisopropyl ester (35). To a solution of 34 (55.0 mg, 39.3 μmol, 1.00 equiv) in anhydrous THF (0.12 mL, 0.33 M), triethylamine trihydrofluoride (157 μL, 962 μmol, 20.0 equiv) was added. The reaction mixture was stirred for 3 h before a second addition of triethylamine trihydrofluoride (157 μL, 962 μmol, 20.0 equiv) was added dropwise. After 2 h, the reaction mixture was diluted with EtOAc (2 mL) and a saturated solution of NH4Cl (2 mL) was added. The aqueous layer was extracted with EtOAc (2 x 2 mL), and the organic layers were combined, washed with brine (5 mL), dried over MgSO4, filtered and concentrated in vacuo. Purification by flash chromatography (Hexanes/EtOAc, 20:80) provided 35 (40 mg, 94%) as a clear oil. Rf = 0.35 (Hexanes/EtOAc, 30:70); [α]D25 -66 (c 0.8, CHCl3); C61H68O18; MW = 1089.1970 gmol-1; IR (neat, cm-1) νmax 3462, 3060, 2981, 1731, 1454, 1272; 1H NMR (500 MHz, CDCl3) δ (ppm) 8.30 – 8.24 (m, 2H), 7.57 – 7.14 (m, 23H), 6.06 (dd, J = 10.1, 3.4 Hz, 1H), 5.88 (dd, J = 10.1, 2.7 Hz, 1H), 5.52 (d, J = 7.7 Hz, 1H), 5.43 (dd, J = 10.0, 7.7 Hz, 1H), 5.16 (d, J = 12.1 Hz, 1H), 5.08 (hept, J = 6.3 Hz, 1H), 5.00 – 4.89 (m, 3H), 4.88 (t, J = 3.0 Hz, 1H), 4.87 – 4.81 (m, 2H), 4.80 – 4.71 (m, 5H), 4.62 (d, J = 11.6 Hz, 1H), 4.50 (dd, J = 10.3, 2.8 Hz, 1H), 4.21 (q, J = 6.6 Hz, 1H), 4.10 (s, 1H), 4.00 (dd, J = 10.3, 3.9 Hz, 1H), 3.93 (d, J = 10.1 Hz, 1H), 3.89 (dd, J = 12.1, 8.9 Hz, 1H), 3.73 – 3.69 (m, 1H), 3.60 (d, J = 12.2 Hz, 1H), 3.50 (dd, J = 8.9, 2.4 Hz, 1H), 2.43 (s, 1H), 1.28 (d, J = 6.3 Hz, 3H), 1.24 (d, J = 6.2 Hz, 3H), 1.12 (d, J = 6.3 Hz, 3H), 1.06 (d, J = 6.2 Hz, 3H), 1.02 (d, J = 6.5 Hz, 3H); 13C{1H} NMR (126 MHz, CDCl3) δ (ppm) 169.6, 168.6, 167.7, 166.4, 139.3, 138.8, 138.7, 135.3, 132.7, 130.7, 130.5, 128.8, 128.70, 128.67, 128.6, 128.5, 128.41, 128.39, 128.38, 128.33, 128.2, 128.1, 127.8, 127.54, 127.52, 127.3, 99.2, 99.1, 79.1, 77.5, 77.4, 76.6, 76.5, 75.9, 75.7, 74.9, 73.5, 73.3, 72.5, 71.0, 70.4, 69.6, 67.7, 67.0, 66.1, 59.7, 21.82, 21.77, 21.71, 21.67, 16.7; HRMS calcd for C61H68O18Na [M+Na+]: 1111.4303, found 1111.4267 (-2.8 ppm). (2R,3R)-2-O-(2,6-di-O-benzoyl-3-O,4-C-((1S)benzyloxycarbonylprop-2-en-1,3-diyl)-β-Dgalactopyranosyl)-3-O-(2,3,4-tri-O-benzyl-α-Lfucopyranosyl)-tartaric acid diisopropyl ester (36). To a solution of 35 (21.0 mg, 19.3 μmol, 1.00 equiv) in dichloromethane (0.19 mL, 0.10 M), pyridine (4.7 μL, 58 μmol, 3.0 equiv) and benzoyl chloride (3.4 μL, 29 μmol, 1.5 equiv) were added. After stirring for 16 h at 25 °C, a saturated solution of NaHCO3 (2 mL) was added. The aqueous layer was extracted with EtOAc (2 x 2 mL), and the combined organic layers were washed with brine (5 mL), dried over MgSO4, filtered, and concentrated in vacuo. Purification by flash chromatography (Hexanes/EtOAc, 70:30) provided 36 (20 mg, 87%) as a white foam. Rf = 0.15 (Hexanes/EtOAc, 70:30); [α]D25 -45 (c 0.6, CHCl3); C68H72O19; MW = 1193.3050 gmol-1; IR (neat, cm-1) νmax 3473, 3038, 2979, 1727, 1453, 1270; 1H NMR (500 MHz, CDCl3) δ (ppm) 8.16 – 8.10 (m, 2H), 8.11 – 8.06 (m, 2H), 7.61 – 7.54 (m, 1H),



7.51 – 7.43 (m, 3H), 7.41 – 7.33 (m, 4H), 7.32 – 7.24 (m, 12H), 7.22 – 7.14 (m, 6H), 6.24 (dd, J = 10.2, 2.6 Hz, 1H), 6.10 (dd, J = 10.2, 3.4 Hz, 1H), 5.51 (dd, J = 10.1, 7.2 Hz, 1H), 5.12 – 5.05 (m, 2H), 5.00 (d, J = 12.1 Hz, 1H), 4.97 – 4.81 (m, 6H), 4.80 – 4.68 (m, 2H), 4.72 – 4.65 (m, 2H), 4.61 (d, J = 11.7 Hz, 1H), 4.54 (d, J = 11.5 Hz, 1H), 4.44 – 4.43 (m, 2H), 4.06 – 3.97 (m, 2H), 3.91 (t, J = 2.9 Hz, 2H), 3.53 (dd, J = 6.7, 3.7 Hz, 1H), 3.50 – 3.45 (m, 1H), 2.52 (s, 1H), 1.17 (m, 9H), 1.12 (d, J = 6.3 Hz, 3H), 0.96 (d, J = 6.5 Hz, 3H); 13C{1H} NMR (126 MHz, CDCl3) δ (ppm) 168.6, 168.4, 167.8, 166.5, 166.0, 139.1, 139.0, 138.9, 135.2, 133.4, 133.0, 130.5, 130.1, 129.95, 129.93, 128.84, 128.75, 128.71, 128.67, 128.44, 128.42, 128.40, 128.38, 128.36, 128.3, 128.2, 127.8, 127.6, 127.49, 127.45, 127.4, 100.4, 99.8, 79.7, 78.5, 77.8, 77.7, 77.4, 75.5, 74.9, 74.8, 73.2, 73.0, 72.7, 70.9, 69.3, 69.1, 67.4, 67.2, 66.4, 62.6, 21.77, 21.75, 21.74, 21.72, 16.6; HRMS calcd for C68H72O19Na [M+Na+]: 1215.4560, found 1215.4557 (-0.2 ppm). (2R,3R)-2-O-(2-O-benzoyl-3-O,4-C(benzyloxycarbonylprop-1-en-1,3-diyl)-β-Dgalactopyranosyl)-3-O-(2,3,4-tri-O-benzyl-α-Lfucopyranosyl)-tartaric acid diisopropyl ester (37). To a solution of 34 (100 mg, 71.4 μmol, 1.00 equiv) in anhydrous THF (0.30 mL, 0.24 M), TBAF (0.21 mL, 1.0 M in THF, 3.0 equiv) was added dropwise. The reaction mixture was stirred for 1 h before being diluted with EtOAc (2 mL) and a saturated solution of NH4Cl (2 mL) was added. The aqueous layer was extracted with EtOAc (2 x 2 mL), and the organic layers were combined, washed with brine (5 mL), dried over MgSO4, filtered and concentrated in vacuo. Purification by flash chromatography (Hexanes/EtOAc, 50:50) provided 37 (75 mg, 96%) as a clear oil. Rf = 0.35 (Hexanes/EtOAc, 50:50); [α]D25 -54 (c 0.3, CHCl3); C61H68O18; MW = 1089.1970 gmol-1; IR (neat, cm-1) νmax 3473, 3038, 2979, 1729, 1454, 1272; 1H NMR (500 MHz, CDCl3) δ (ppm) 8.30 (dd, J = 8.3, 1.4 Hz, 2H), 7.64 – 7.56 (m, 1H), 7.55 – 7.46 (m, 6H), 7.43 – 7.36 (m, 2H), 7.38 – 7.32 (m, 1H), 7.31 (dd, J = 4.2, 1.2 Hz, 4H), 7.31 – 7.26 (m, 1H), 7.24 – 7.17 (m, 3H), 7.16 – 7.06 (m, 4H), 6.82 – 6.76 (m, 1H), 5.91 (dd, J = 5.1, 2.7 Hz, 1H), 5.59 (d, J = 8.3 Hz, 1H), 5.31 (d, J = 12.6 Hz, 1H), 5.28 (dd, J = 10.1, 8.3 Hz, 1H), 5.12 (hept, J = 6.2 Hz, 1H), 5.04 – 4.92 (m, 4H), 4.88 – 4.82 (m, 4H), 4.80 (dd, J = 10.3, 2.8 Hz, 1H), 4.69 – 4.61 (m, 3H), 4.34 (d, J = 12.0 Hz, 1H), 4.17 (q, J = 6.5 Hz, 1H), 4.05 (dd, J = 10.3, 3.9 Hz, 1H), 3.84 (dd, J = 12.2, 9.7 Hz, 1H), 3.72 (d, J = 2.4 Hz, 1H), 3.56 – 3.48 (m, 2H), 2.29 (d, J = 10.2 Hz, 1H), 2.11 (s, 1H), 1.85 (ddd, J = 18.6, 5.2, 1.7 Hz, 1H), 1.61 (dd, J = 18.5, 2.9 Hz, 1H), 1.30 (d, J = 6.3 Hz, 3H), 1.27 (t, J = 6.6 Hz, 6H), 1.15 (d, J = 6.2 Hz, 3H), 1.01 (d, J = 6.5 Hz, 3H); 13C{1H} NMR (126 MHz, CDCl ) δ (ppm) 169.6, 168.2, 166.1, 3 161.7, 143.7, 139.4, 138.5, 138.2, 135.9, 132.8, 130.8, 130.4, 129.3, 128.9, 128.69, 128.67, 128.5, 128.4, 128.2, 128.1, 127.89, 127.85, 127.75, 127.64, 127.63, 109.7, 97.7, 97.6, 79.2, 78.7, 78.2, 77.4, 76.8, 75.1, 75.0, 74.6, 74.4, 73.3, 70.9, 70.4, 69.9, 67.73, 67.65, 66.4, 59.9, 31.0, 22.1, 21.80, 21.76, 21.67, 16.7; HRMS calcd for C61H68O18Na [M+Na+]: 1111.4303, found 1111.4288 (-0.9 ppm). (2R,3R)-2-O-(2,6-di-O-benzoyl-3-O,4-C(benzyloxycarbonylprop-1-en-1,3-diyl)-β-Dgalactopyranosyl)-3-O-(2,3,4-tri-O-benzyl-α-Lfucopyranosyl)-tartaric acid diisopropyl ester (38). Following a similar procedure as in 36, to a solution of 37

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(40.0 mg, 36.7 μmol, 1.00 equiv) in dichloromethane (0.37 mL, 0.10 M), pyridine (12 μL, 0.15 mmol, 4.0 equiv) and benzoyl chloride (6.4 μL, 55 μmol, 1.5 equiv) were added. Purification by flash chromatography (Hexanes/EtOAc, 70:30) provided 38 (41 mg, 94%) as a white foam. Rf = 0.11 (Hexanes/EtOAc, 70:30); [α]D25 -39 (c 0.7, CHCl3); C68H72O19; MW = 1193.3050 gmol-1; IR (neat, cm-1) νmax 3480, 2981, 1724, 1453, 1269; 1H NMR (500 MHz, CDCl3) δ (ppm) 8.07 (ddd, J = 19.6, 8.2, 1.4 Hz, 4H), 7.55 (q, J = 7.2 Hz, 2H), 7.43 (td, J = 7.8, 6.2 Hz, 5H), 7.40 – 7.33 (m, 2H), 7.33 – 7.25 (m, 8H), 7.26 – 7.11 (m, 8H), 7.02 (t, J = 7.4 Hz, 1H), 6.00 (dd, J = 5.3, 2.7 Hz, 1H), 5.44 (dd, J = 10.0, 8.0 Hz, 1H), 5.30 – 5.20 (m, 2H), 5.04 (d, J = 12.6 Hz, 1H), 5.00 – 4.93 (m, 3H), 4.88 (d, J = 11.5 Hz, 1H), 4.83 – 4.74 (m, 2H), 4.72 – 4.65 (m, 2H), 4.64 – 4.54 (m, 3H), 4.52 – 4.45 (m, 2H), 4.10 (q, J = 6.4 Hz, 1H), 3.99 (dd, J = 10.2, 3.7 Hz, 1H), 3.90 (dd, J = 10.2, 2.7 Hz, 1H), 3.54 – 3.46 (m, 2H), 2.96 (d, J = 10.0 Hz, 1H), 2.50 (s, 1H), 2.18 (dd, J = 21.0, 4.0 Hz, 1H), 1.95 (d, J = 18.9 Hz, 1H), 1.23 – 1.14 (m, 12H), 1.00 (d, J = 6.4 Hz, 3H); 13C{1H} NMR (126 MHz, CDCl3) δ (ppm) 168.2, 167.9, 166.4, 165.5, 161.6, 143.7, 138.76, 138.73, 138.7, 135.7, 133.4, 133.0, 130.5, 130.01, 129.96, 129.91, 128.8, 128.55, 128.53, 128.50, 128.44, 128.41, 128.3, 128.1, 128.0, 127.92, 127.85, 127.7, 127.6, 127.3, 109.5, 99.2, 99.0, 80.0, 78.3, 78.0, 77.4, 76.38, 76.36, 75.9, 74.9, 73.9, 72.8, 70.6, 69.5, 69.3, 68.1, 67.5, 66.6, 62.2, 31.3, 21.79, 21.78, 21.77, 21.73, 16.6; HRMS calcd for C68H72O19Na [M+Na+]: 1215.4560, found 1215.4549 (-0.9 ppm). (2R,3R)-2-O-(2-O-benzoyl-3-O,4-C-((S)-carboxyprop-1,3diyl)-β-D-galactopyranosyl)-3-O-(α-L-fucopyranosyl)tartaric acid diisopropyl ester (1). To a solution of 35 (16.0 mg, 14.7 μmol, 1.00 equiv) in THF (1.2 mL, 0.010 M), palladium hydroxide (20 wt. %) on carbon (15.5 mg, 22.0 μmol, 1.50 equiv) was added. The reaction mixture was degassed and flushed with a hydrogen filled balloon. After stirring at 25 °C under a standard hydrogen atmosphere for 16 h, the reaction mixture was filtered through Celite, washed with methanol, and concentrated in vacuo. Purification by reverse phase C18 (H2O/MeOH, 60:40) provided 1 (9.3 mg, 87%) as a white powder. [α]D25 -108 (c 0.1, MeOH); C33H46O18; MW = 730.7130 gmol-1; IR (neat, cm1) ν 1 max 3392, 2982, 1758, 1718, 1592, 1277; H NMR (500 MHz, CD3OD) δ (ppm) 8.16 (d, J = 7.4 Hz, 2H), 7.58 (t, J = 7.5 Hz, 1H), 7.47 (d, J = 7.6 Hz, 2H), 5.36 (dd, J = 10.2, 7.8 Hz, 1H), 5.08 (hept, J = 6.3 Hz, 1H), 4.79 – 4.74 (m, 2H), 4.71 – 4.63 (m, 2H), 4.40 (d, J = 3.1 Hz, 1H), 4.31 (d, J = 10.3 Hz, 1H), 4.20 (d, J = 6.3 Hz, 1H), 4.08 (q, J = 6.5 Hz, 1H), 3.81 (dd, J = 11.8, 3.2 Hz, 1H), 3.74 – 3.65 (m, 2H), 3.62 (dd, J = 10.2, 3.9 Hz, 1H), 3.53 (dd, J = 3.2, 1.2 Hz, 1H), 3.39 (dd, J = 6.8, 3.2 Hz, 1H), 2.29 – 2.18 (m, 1H), 2.06 (d, J = 13.5 Hz, 1H), 1.67 (d, J = 12.5 Hz, 1H), 1.59 (td, J = 13.4, 4.3 Hz, 1H), 1.29 (dd, J = 6.3, 5.2 Hz, 6H), 1.19 (d, J = 6.3 Hz, 3H), 1.06 (d, J = 6.2 Hz, 3H), 0.99 (d, J = 6.5 Hz, 3H) (Labile protons were not observed due to exchange with deuterated solvent); 13C{1H} NMR (126 MHz, CD3OD) δ (ppm) 178.8, 170.7, 168.9, 168.4, 133.9, 131.9, 131.4, 129.2, 103.4, 103.2, 80.6, 79.1, 78.9, 76.4, 76.0, 73.5, 72.6, 71.6, 71.5, 70.7, 70.5, 69.9, 68.7, 60.9, 28.8, 23.0, 22.1, 21.99, 21.94, 21.8, 16.4; HRMS calcd for C33H46O18Na [M+Na+]: 753.2582, found 753.2582 (+0.7 ppm). (2R,3R)-2-O-(2-O-benzoyl-3-O,4-C-((R)-carboxyprop-1,3diyl)-β-D-galactopyranosyl)-3-O-(α-L-fucopyranosyl)-


Page 17 of 20 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


tartaric acid diisopropyl ester (3). Following a similar procedure as in 1, to a solution of 37 (35.0 mg, 32.1 μmol, 1.00 equiv) in THF (0.64 mL, 0.050 M), palladium hydroxide (20 wt. %) on carbon (33.8 mg, 48.2 μmol, 1.50 equiv) was added. Purification by reverse phase C18 (H2O/MeOH, 60:40) provided 3 (20 mg, 85%) as a white powder. [α]D25 45 (c 0.6, MeOH); IR (neat, cm-1) νmax 3374, 2981, 1726, 1603, 1277; C33H46O18; MW = 730.7130 gmol-1; 1H NMR (500 MHz, CD3OD) δ (ppm) 8.09 (d, J = 7.4, 2H), 7.61 (t, J = 7.4 Hz, 1H), 7.47 (t, J = 7.8 Hz, 2H), 5.39 (dd, J = 10.0, 7.8 Hz, 1H), 5.07 (hept, J = 6.3 Hz, 1H), 4.89 (d, J = 8.0 Hz, 1H), 4.86 – 4.80 (m, 1H), 4.80 (d, J = 3.5 Hz, 1H), 4.71 (d, J = 3.1 Hz, 1H), 4.41 (d, J = 3.0 Hz, 1H), 4.05 (appq, J = 6.5 Hz, 1H), 3.87 (dd, J = 10.9, 3.6 Hz, 1H), 3.83 (dd, J = 11.9, 3.3 Hz, 1H), 3.77 (dd, J = 11.8, 6.4 Hz, 1H), 3.67 – 3.61 (m, 3H), 3.52 – 3.47 (m, 2H), 1.95 – 1.81 (m, 3H), 1.64 (td, J = 12.8, 5.6 Hz, 1H), 1.34 – 1.26 (m, 6H), 1.24 (d, J = 6.1 Hz, 3H), 1.13 (d, J = 6.5 Hz, 3H), 1.00 (d, J = 6.7 Hz, 3H) (Labile protons were not observed due to exchange with deuterated solvent); 13C{1H} NMR (126 MHz, CD3OD) δ (ppm) 178.9, 170.4, 169.3, 168.4, 134.5, 131.3, 131.2, 129.4, 103.3, 102.6, 81.5, 81.1, 80.2, 79.2, 78.8, 73.5, 72.6, 71.5, 71.4, 70.7, 70.4, 69.8, 68.7, 60.9, 31.8, 25.4, 22.1, 21.99, 21.94, 21.88, 16.5; HRMS calcd for C33H46O18Na [M+Na+]: 753.2582, found 753.2583 (+0.9 ppm). (2R,3R)-2-O-(2,6-di-O-benzoyl-3-O,4-C-((S)-carboxyprop1,3-diyl)-β-D-galactopyranosyl)-3-O-(α-L-fucopyranosyl)tartaric acid diisopropyl ester (2). Following a similar procedure as in 1, to a solution of 36 (65.0 mg, 54.5 μmol, 1.00 equiv) in THF (2.2 mL, 0.030 M), palladium hydroxide (20 wt. %) on carbon (57.4 mg, 817 μmol, 1.50 equiv) was added. Purification by reverse phase C18 (H2O/MeOH, 60:40) provided 2 (24 mg, 53%) as a white powder. [α]D25 41 (c 0.2, MeOH); C40H50O19; MW = 834.8210 gmol-1; IR (neat, cm-1) νmax 3375, 2980, 1719, 1602, 1271; 1H NMR (500 MHz, CD3OD) δ (ppm) 8.16 (dd, J = 8.3, 1.4 Hz, 2H), 8.05 (dd, J = 8.4, 1.3 Hz, 2H), 7.67 – 7.59 (m, 1H), 7.61 – 7.54 (m, 1H), 7.53 – 7.43 (m, 4H), 5.40 (dd, J = 10.3, 7.8 Hz, 1H), 4.94 (hept, J = 6.3 Hz, 1H), 4.84 (d, J = 7.8 Hz, 1H), 4.66 (d, J = 3.9 Hz, 1H), 4.66 – 4.60 (m, 2H), 4.56 (dd, J = 11.8, 3.3 Hz, 1H), 4.43 (dd, J = 11.8, 7.7 Hz, 1H), 4.38 (d, J = 10.3 Hz, 1H), 4.36 (d, J = 3.6 Hz, 1H), 4.22 (d, J = 6.3 Hz, 1H), 4.08 (appq, J = 6.4 Hz, 1H), 3.81 (dd, J = 7.7, 3.3 Hz, 1H), 3.68 (dd, J = 10.2, 3.2 Hz, 1H), 3.61 (dd, J = 10.2, 4.0 Hz, 1H), 3.54 (dd, J = 3.3, 1.2 Hz, 1H), 2.25 (m, 1H), 2.09 (dt, J = 14.7, 3.7 Hz, 1H), 1.78 – 1.69 (m, 1H), 1.68 (dd, J = 13.2, 4.5 Hz, 1H), 1.19 (d, J = 6.3 Hz, 3H), 1.15 (d, J = 6.3 Hz, 3H), 1.10 (d, J = 6.3 Hz, 3H), 1.02 (d, J = 6.2 Hz, 3H), 1.00 (d, J = 6.6 Hz, 3H) (Labile protons were not observed due to exchange with deuterated solvent); 13C{1H} NMR (126 MHz, CD OD) δ (ppm) 178.7, 170.5, 3 168.9, 168.1, 167.8, 134.4, 133.9, 132.0, 131.4, 131.3, 130.7, 129.6, 129.2, 103.5, 103.1, 79.19, 79.16, 78.3, 76.3, 76.0, 73.5, 72.4, 71.6, 71.5, 70.6, 70.4, 69.9, 68.7, 63.8, 28.8, 23.0, 22.1, 21.89, 21.84, 21.82, 16.5; HRMS calcd for C40H50O19Na [M+Na+]: 857.2844, found 857.2837 (-0.2 ppm). (2R,3R)-2-O-(2,6-di-O-benzoyl-3-O,4-C-((R)-carboxyprop1,3-diyl)-β-D-galactopyranosyl)-3-O-(α-L-fucopyranosyl)tartaric acid diisopropyl ester (4). Following a similar procedure as in 1, to a solution of 38 (19.2 mg, 16.1 μmol, 1.00 equiv) in THF (1.3 mL, 0.010 M), palladium hydroxide (20 wt. %) on carbon (16.9 mg, 24.1 μmol, 1.50 equiv) was added. Purification by reverse phase C18 (H2O/MeOH,

60:40) provided 4 (13 mg, 93%) as a white powder. [α]D25 26 (c 0.8, MeOH); C40H50O19; MW = 834.8210 gmol-1; IR (neat, cm-1) νmax 3431, 2980, 1720, 1453, 1271; 1H NMR (500 MHz, CD3OD) δ (ppm) 8.07 (dd, J = 8.3, 1.4 Hz, 4H), 7.66 – 7.56 (m, 2H), 7.54 – 7.44 (m, 4H), 5.45 (dd, J = 10.1, 7.9 Hz, 1H), 4.95 (hept, J = 6.2 Hz, 1H), 4.92 (d, J = 7.8 Hz, 1H), 4.79 – 4.72 (m, 1H), 4.68 (d, J = 3.8 Hz, 1H), 4.65 (dd, J = 11.9, 3.1 Hz, 1H), 4.62 (d, J = 4.0 Hz, 1H), 4.46 (dd, J = 11.9, 8.0 Hz, 1H), 4.33 (d, J = 4.1 Hz, 1H), 4.01 (appq, J = 6.6 Hz, 1H), 3.89 (dd, J = 10.8, 3.0 Hz, 1H), 3.87 (dd, J = 7.7, 2.7 Hz, 1H), 3.68 (d, J = 10.1 Hz, 1H), 3.64 (dd, J = 10.2, 3.1 Hz, 1H), 3.60 (dd, J = 10.2, 3.8 Hz, 1H), 3.50 (dd, J = 3.1, 1.2 Hz, 1H), 1.98 – 1.86 (m, 3H), 1.73 (td, J = 13.4, 6.0 Hz, 1H), 1.19 (t, J = 6.3 Hz, 6H), 1.15 (d, J = 6.3 Hz, 3H), 1.06 (d, J = 6.2 Hz, 3H), 0.99 (d, J = 6.7 Hz, 3H) (Labile protons were not observed due to exchange with deuterated solvent); 13C{1H} NMR (126 MHz, CD3OD) δ (ppm) 179.0, 170.0, 169.2, 167.9, 167.7, 134.4, 134.3, 131.5, 131.4, 131.1, 130.7, 129.6, 129.4, 103.1, 103.0, 81.29, 81.26, 79.3, 79.1, 78.0, 73.5, 72.2, 71.6, 71.3, 70.6, 70.2, 70.0, 68.7, 64.0, 32.0, 25.4, 22.0, 21.90, 21.86, 21.85, 16.5; HRMS calcd for C40H50O19Na [M+Na+]: 857.2844, found 857.2846 (+0.9 ppm).

ASSOCIATED CONTENT Supporting Information. This material is available free of charge via the Internet at http://pubs.acs.org 1H NMR and 13C{1H} NMR spectra for all new compounds along with proofs of structure. Modified methods for bioassays along with details concerning the computational method, energies, and Cartesian coordinates for all of the transition structures and intermediate geometries

AUTHOR INFORMATION Corresponding Authors *E-mail: [email protected]. *E-mail: [email protected]. *E-mail: [email protected]. *E-mail: [email protected]. Notes The authors declare no competing financial interest.

ACKNOWLEDGMENT Funding for this research has been granted from the Canadian Glycomics Network (Glyconet http://doi.org/10.13039/501100009056), and in part from Natural Sciences and Engineering Research Council, NSERC, RGPIN-2015-06405. This research was enabled in part by WestGrid (www.westgrid.ca) and Compute Canada−Calcul Canada (www. computecanada.ca). In memory of Donald Jobin (MSc 2004) for his synthetic work towards these scaffolds.

REFERENCES 1) Ernst, B.; Magnani, J. L., From carbohydrate leads to glycomimetic drugs. Nat. Rev. Drug. Discov. 2009, 8, 661.



2) Simanek, E. E.; McGarvey, G. J.; Jablonowski, J. A.; Wong, C.-H., Selectin−Carbohydrate Interactions: From Natural Ligands to Designed Mimics. Chem. Rev. 1998, 98, 833. 3) Magnani, J. L., The discovery, biology, and drug development of sialyl Lea and sialyl Lex. Arch. Biochem. Biophys. 2004, 426, 122. 4) Calosso, M.; Tambutet, G.; Charpentier, D.; StPierre, G.; Vaillancourt, M.; Bencheqroun, M.; Gratton, J. P.; Prevost, M.; Guindon, Y., Acyclic tethers mimicking subunits of polysaccharide ligands: selectin antagonists. ACS Med. Chem. Lett. 2014, 5, 1054. 5) Bevilacqua, M. P., Endothelial-leukocyte adhesion molecules. Annu. Rev. Immunol. 1993, 11, 767. 6) Thoma, G.; Magnani, J. L.; Patton, J. T.; Ernst, B.; Jahnke, W., Preorganization of the Bioactive Conformation of Sialyl LewisX Analogues Correlates with Their Affinity to E-Selectin. Angew. Chem. Int. Ed. 2001, 40, 1941. 7) Krishnamurthy, V. R.; Sardar, M. Y.; Ying, Y.; Song, X.; Haller, C.; Dai, E.; Wang, X.; Hanjaya-Putra, D.; Sun, L.; Morikis, V.; Simon, S. I.; Woods, R. J.; Cummings, R. D.; Chaikof, E. L., Glycopeptide analogues of PSGL-1 inhibit Pselectin in vitro and in vivo. Nat. Commun. 2015, 6, 6387. 8) Natoni, A.; Macauley, M. S.; O'Dwyer, M. E., Targeting Selectins and Their Ligands in Cancer. Front. Oncol. 2016, 6, 93. 9) Chang, J.; Patton, J. T.; Sarkar, A.; Ernst, B.; Magnani, J. L.; Frenette, P. S., GMI-1070, a novel pan-selectin antagonist, reverses acute vascular occlusions in sickle cell mice. Blood 2010, 116, 1779. 10) Somers, W. S.; Tang, J.; Shaw, G. D.; Camphausen, R. T., Insights into the Molecular Basis of Leukocyte Tethering and Rolling Revealed by Structures of P- and E-Selectin Bound to SLeX and PSGL-1. Cell 2000, 103, 467. 11) Leppanen, A.; White, S. P.; Helin, J.; McEver, R. P.; Cummings, R. D., Binding of glycosulfopeptides to P-selectin requires stereospecific contributions of individual tyrosine sulfate and sugar residues. J. Biol. Chem. 2000, 275, 39569. 12) Rinnbauer, M.; Ernst, B.; Wagner, B.; Magnani, J.; Benie, A. J.; Peters, T., Epitope mapping of sialyl Lewis(x) bound to E-selectin using saturation transfer difference NMR experiments. Glycobiology 2003, 13, 435. 13) Kolb, H. C.; Ernst, B., Development of Tools for the Design of Selectin Antagonists. Chem. Eur. J. 1997, 3, 1571. 14) Preston, R. C.; Jakob, R. P.; Binder, F. P.; Sager, C. P.; Ernst, B.; Maier, T., E-selectin ligand complexes adopt an extended high-affinity conformation. J. Mol. Cell. Biol. 2016, 8, 62. 15) Calosso, M.; Charpentier, D.; Vaillancourt, M.; Bencheqroun, M.; St-Pierre, G.; Wilkes, B. C.; Guindon, Y., A new approach to explore the binding space of polysaccharide-based ligands: selectin antagonists. ACS Med. Chem. Lett. 2012, 3, 1045. 16) Schwizer, D.; Patton, J. T.; Cutting, B.; Smiesko, M.; Wagner, B.; Kato, A.; Weckerle, C.; Binder, F. P.; Rabbani, S.; Schwardt, O.; Magnani, J. L.; Ernst, B., Pre-organization of the core structure of E-selectin antagonists. Chem. Eur. J. 2012, 18, 1342.

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17) Guindon, Y.; Ogilvie, W. W.; Bordeleau, J.; Cui, W. L.; Durkin, K.; Gorys, V.; Juteau, H.; Lemieux, R.; Liotta, D.; Simoneau, B.; Yoakim, C., Opening of tartrate acetals using dialkylboron bromide: evidence for stereoselectivity downstream from ring fission. J. Am. Chem. Soc. 2003, 125, 428. 18) Kranich, R.; Busemann, A. S.; Bock, D.; SchroeterMaas, S.; Beyer, D.; Heinemann, B.; Meyer, M.; Schierhorn, K.; Zahlten, R.; Wolff, G.; Aydt, E. M., Rational design of novel, potent small molecule pan-selectin antagonists. J. Med. Chem. 2007, 50, 1101. 19) Titz, A.; Ernst, B., Mimetics of Sialyl Lewis X: The Pre-Organization of the Carboxylic Acid is Essential for Binding to Selectins. CHIMIA 2007, 61, 194. 20) Thoma, G.; Schwarzenbach, F.; Duthaler, R. O., Synthesis of a Sialyl Lewis x Mimic with Fixed Carboxylic Acid Group: Chemical Approach toward the Elucidation of the Bioactive Conformation of Sialyl Lewis x. J. Org. Chem. 1996, 61, 514. 21) Borowski, D.; Zweiböhmer, T.; Ziegler, T., 1,2Annulated Sugars: Synthesis of Polyhydroxylated 2,10Dioxadecalins with β-manno Configuration. Eur. J. Org. Chem. 2016, 2016, 5248. 22) Doddi, V. R.; Kancharla, P. K.; Reddy, Y. S.; Kumar, A.; Vankar, Y. D., Synthesis of fused pyrancarbahexopyranoses as glycosidase inhibitors. Carbohydr. Res. 2009, 344, 606. 23) Ansari, A. A.; Rajasekaran, P.; Khan, M. M.; Vankar, Y. D., Bicyclic hybrid sugars as glycosidase inhibitors: synthesis and comparative study of inhibitory activities of fused oxa-oxa, oxa-aza, and oxa-carbasugar hybrid molecules. J. Org. Chem. 2014, 79, 1690. 24) Lazzara, N. C.; Rosano, R. J.; Vagadia, P. P.; Giovine, M. T.; Bezpalko, M. W.; Piro, N. A.; Kassel, W. S.; Boyko, W. J.; Zubris, D. L.; Schrader, K. K.; Wedge, D. E.; Duke, S. O.; Giuliano, R. M. Synthesis and Biological Evaluation of 6[(1R)-1-Hydroxyethyl]-2,4a(R),6(S),8a(R)tetrahydropyrano-[3,2- b]-pyran-2-one and Structural Analogues of the Putative Structure of Diplopyrone. J. Org. Chem. 2019, 84, 666. 25) Mandhapati, A. R.; Yang, G.; Kato, T.; Shcherbakov, D.; Hobbie, S. N.; Vasella, A.; Bottger, E. C.; Crich, D. Structure-Based Design and Synthesis of Apramycin– Paromomycin Analogues: Importance of the Configuration at the 6′-Position and Differences between the 6′-Amino and Hydroxy Series. J. Am. Chem. Soc. 2017, 139, 14611. 26) Aboussafy, C. L.; Andersen Gersby, L. B.; Molinaro, A.; Newman, M. A.; Lowary, T. L. A Convergent Route to Enantiomers of the Bicyclic Monosaccharide Bradyrhizose Leads to Insight into the Bioactivity of an Immunologically Silent Lipopolysaccharide. J. Org. Chem. 2019, 84, 14. 27) Li, W.; Silipo, A.; Gersby, L. B.; Newman, M. A.; Molinaro, A.; Yu, B. Synthesis of Bradyrhizose Oligosaccharides Relevant to the Bradyrhizobium O-Antigen. Angew. Chem. Int. Ed. 2017, 56, 2092. 28) Dharuman, S.; Crich, D., Determination of the Influence of Side-Chain Conformation on Glycosylation Selectivity using Conformationally Restricted Donors. Chem. Eur. J. 2016, 22, 4535.


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29) Amarasekara, H.; Dharuman, S.; Kato, T.; Crich, D., Synthesis of Conformationally-Locked cis- and transBicyclo[4.4.0] Mono-, Di-, and Trioxadecane Modifications of Galacto- and Glucopyranose; Experimental Limiting 3JH,H Coupling Constants for the Estimation of Carbohydrate Side Chain Populations and Beyond. J. Org. Chem. 2018, 83, 881. 30) Misra, A. K.; Das, S. K.; Roy, N., Preparation oftransDiequatorial 2,3-Pyruvate Acetals in a Di- and a Trisaccharide Related to the K-Antigen from E. Coli 0101:K103:H−. Synth. Commun. 1998, 28, 1471. 31) Chan, K.-K.; Cohen, N.; De Noble, J. P.; Specian, A. C.; Saucy, G., Synthetic studies on (2R,4'R,8'R)-.alpha.tocopherol. Facile syntheses of optically active, saturated, acyclic isoprenoids via stereospecific [3,3] sigmatropic rearrangements. J. Org. Chem. 1976, 41, 3497. 32) Chan, K.-K.; Specian, A. C.; Saucy, G., Synthesis of (2R,4'R,8'R)-α-tocopheryl acetate (vitamin E acetate) using [3,3] sigmatropic rearrangement. J. Org. Chem. 1978, 43, 3435. 33) Miljkovic, M.; Gligorijevic, M.; Satoh, T.; Miljkovic, D., Synthesis of macrolide antibiotics. I. Stereospecific addition of methyllithium and methylmagnesium iodide to methyl α-D-xylo-hexopyranosid-4-ulose derivatives. Determination of the configuration at the branching carbon atom by carbon-13 nuclear magnetic resonance spectroscopy. J. Org. Chem. 1974, 39, 1379. 34) Miljkovic, M., Carbohydrates: Synthesis, Mechanisms, and Stereoelectronic Effects, Springer, New York, 2009. 35) Guo, M.; Li, D.; Zhang, Z., Novel synthesis of 2-oxo3-butynoates by copper-catalyzed cross-coupling reaction of terminal alkynes and monooxalyl chloride. J. Org. Chem. 2003, 68, 10172. 36) Noyori, R.; Tomino, I.; Tanimoto, Y.; Nishizawa, M., Asymmetric synthesis via axially dissymmetric molecules. 6. Rational designing of efficient chiral reducing agents. Highly enantioselective reduction of aromatic ketones by binaphthol-modified lithium aluminum hydride reagents. J. Am. Chem. Soc. 1984, 106, 6709. 37) Pasto, D. J.; Taylor, R. T., Reduction with Diimide, Org. React. 1992, 40, 91. 38) Cusack, N. J.; Reese, C. B.; Risius, A. C.; Roozepeikar, B., 2,4,6-Tri-isopropylbenzenesulphonyl hydrazide: A convenient source of di-imide. Tetrahedron 1976, 32, 2157. 39) Frisch, M. J.; et al. Gaussian 09, revision A.02; Gaussian, Inc.: Wallingford, CT, 2009. 40) Zhao, Y.; Truhlar, D. G., The M06 suite of density functionals for main group thermochemistry, thermochemical kinetics, noncovalent interactions, excited states, and transition elements: two new functionals and systematic testing of four M06-class functionals and 12 other functionals. Theor. Chem. Acc. 2007, 120, 215.

41) Zhao, Y.; Truhlar, D. G., Density functionals with broad applicability in chemistry. Acc. Chem. Res. 2008, 41, 157. 42) Koh, K.; Durst, T., Stereoselective SN2 Reactions of the (R)-Pantolactone Ester of Racemic .alpha.-Halo Carboxylic Acids with Aryl Oxides. A Synthesis of (S)-2Aryloxy and (S)-2-Hydroxy Acids. J. Org. Chem. 1994, 59, 4683. 43) Ben, R. N.; Durst, T., Synthesis of Optically Active αAmino Esters via Dynamic Kinetic Resolution: A Mechanistic Study. J. Org. Chem. 1999, 64, 7700. 44) Huerta, F. F.; Minidis, A. B. E.; Bäckvall, J.-E., Racemisation in asymmetric synthesis. Dynamic kinetic resolution and related processes in enzyme and metal catalysis. Chem. Soc. Rev. 2001, 30, 321. 45) Zhao, Y.; Truhlar, D. G., Computational characterization and modeling of buckyball tweezers: density functional study of concave-convex pi...pi interactions. Phys. Chem. Chem. Phys. 2008, 10, 2813. 46) Ribeiro, R. F.; Marenich, A. V.; Cramer, C. J.; Truhlar, D. G., Use of solution-phase vibrational frequencies in continuum models for the free energy of solvation. J. Phys. Chem. B. 2011, 115, 14556. 47) Legault, C. Y. CYLview, 1.0b, Université de Sherbrooke, 2009, (http://www.cylview.org). 48) The rapid isomerization could also be attributed to a base-induced protonation/deprotonation pathway and is currently being investigated. 49) Seeman, J. I., The Curtin-Hammett principle and the Winstein-Holness equation: new definition and recent extensions to classical concepts. J. Chem. Educ. 1986, 63, 42. 50) Ghoshal, P.; Rajendran, M.; Odo, N.; Ikuta, T., Glycosylation inhibitors efficiently inhibit P-selectinmediated cell adhesion to endothelial cells. PLoS One 2014, 9, e99363. 51) Beste, M. T.; Hammer, D. A., Selectin catch-slip kinetics encode shear threshold adhesive behavior of rolling leukocytes. Proc. Natl. Acad. Sci. USA. 2008, 105, 20716. 52) Waldron, T. T.; Springer, T. A., Transmission of allostery through the lectin domain in selectin-mediated cell adhesion. Proc. Natl. Acad. Sci. USA. 2009, 106, 85. 53) Chakrabarti, S.; Patel, K. D., Regulation of matrix metalloproteinase-9 release from IL-8-stimulated human neutrophils. J. Leukoc. Biol. 2005, 78, 279. 54) Ganguly, A.; Zhang, H.; Sharma, R.; Parsons, S.; Patel, K. D., Isolation of human umbilical vein endothelial cells and their use in the study of neutrophil transmigration under flow conditions. J. Vis. Exp. 2012, 66, e4032.



HO OH Me HO Conformationally Locked

OR2 O

4

Y

O X

O

3

OH O O

OR1

O

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Y = H, X = CO2H 1: R1 = Bz; R2 = H 2: R1 = R2 = Bz

OiPr Y = CO2H, X = H OiPr 3: R1 = Bz; R2 = H 4: R1 = R2 = Bz O

TOC artwork


20

Fused Galactopyranoside Scaffold

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