Ni(II)-Catalyzed Enantioselective Synthesis of β-Hydroxy Esters with

Aug 8, 2019 - A Ni–oxazoline complex-catalyzed asymmetric decarboxylative aldol reaction between malonic acid half-oxyesters and various carbonyls w...
0 downloads 0 Views 1MB Size
Download PDF
Letter Cite This: Org. Lett. XXXX, XXX, XXX−XXX

pubs.acs.org/OrgLett

Ni(II)-Catalyzed Enantioselective Synthesis of β‑Hydroxy Esters with Carboxylate Assistance Na Wang, Hongxin Liu,* Hang Gao, Jiafeng Zhou, Longzhangdi Zheng, Juan Li, Hong-Ping Xiao, Xinhua Li, and Jun Jiang* College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325035, China

Downloaded via RUTGERS UNIV on August 8, 2019 at 23:46:42 (UTC). See https://pubs.acs.org/sharingguidelines for options on how to legitimately share published articles.

S Supporting Information *

ABSTRACT: A Ni−oxazoline complex-catalyzed asymmetric decarboxylative aldol reaction between malonic acid half-oxyesters and various carbonyls with carboxylate assistance was developed, affording structurally diverse β-hydroxy esters with good yields and enantioselectivities under mild conditions. Importantly, the broad substrate scope of this methodology enabled rapid accesses to several natural products and their analogues as exemplified by phenylpropanoid, phaitanthrin B, and phthalide.

nantioenriched β-hydroxy esters, especially α-nonsubstituted ones, are important building blocks1 for the synthesis of various biologically active natural products and pharmaceutical compounds as exemplified by juglomycin A,2 phenylpropanoid,3 fluoxetine,4 duloxetine,5 and atomoxetine6 (Figure 1a). Accordingly, entries to optically active β-hydroxy

E

In this context, silyl ketene acetals were always employed as actual nucleophiles in the Mukaiyama aldol reaction (Figure 1b)8 due to the difficulty of direct catalytic activation of esters (for butyl acetate, pKa = 30.3 in DMSO).9 Despite these achievements, the constructions of β-tertiary hydroxy esters and multifunctional ones are still very challenging, while the multistep preparation of corresponding reactants (β-keto esters and silyl ketene acetals) or extra post-treatment of products in these transformations has always limited the substrate scope, product diversity, and synthetic efficiency. Thus, the development of catalytic, asymmetric, and direct addition of ester to carbonyls, which would provide a facile access to structurally diverse β-hydroxy esters from simple starting materials, is a very challenging but attractive target. Inspired by our previous experience with the synthesis of enantioenriched carboxylic acid10 and given the importance of chiral α-nonsubstituted βhydroxy esters in the synthesis of natural products and pharmaceutical compounds, we began to think about the possibility of exploring a versatile nucleophilic precursor through which rapid synthesis of various β-hydroxy esters could be achieved. A simple retrosynthetic analysis clearly indicated that malonic acid half-oxyesters (MAHOs), which can release CO2 by decarboxylation to produce ester species under mild conditions, would be ideal nucleophiles in the synthesis of β-hydroxy esters. However, compared with active malonic acid half-thioesters (MAHTs), the indirect ester sources that have received a great deal of attention10,11 since the pioneering work of Shair in this field,11b MAHOs always exhibit poorer nucleophilic ability12 due to weaker acidity of

Figure 1. Chiral β-hydroxy ester-derived bioactive compounds and catalytic asymmetric synthesis of β-hydroxy esters.

esters are of widespread interest in the past few decades. For example, great achievements have been made in the catalytic synthesis of chiral β-hydroxy esters by asymmetric hydrogenation of β-keto esters, in which a large number of chiral ligands have been employed and afforded β-hydroxy esters with excellent enantioselectivities (Figure 1b).7 Alternatively, a different approach to this target is the enantioselective introduction of the nucleophilic ester motif into carbonyls. © XXXX American Chemical Society

Received: July 3, 2019

A

DOI: 10.1021/acs.orglett.9b02297 Org. Lett. XXXX, XXX, XXX−XXX

Letter

Organic Letters Table 1. Screening Results of Catalystsa

their methylene protons. As a result, even though Shair et al. achieved the asymmetric decarboxylative aldol reaction between methylmalonic acid half-thioester and aldehydes with high enantioselectivity in 2005,11b MAHOs remain largely unexplored and unexploited in catalytic asymmetric decarboxylative additions despite their great synthetic potential. In the first report of two related transformations, Ma and co-workers reported an asymmetric decarboxylative aldol reaction of 3oxo-3-phenoxypropanoic acid and 2,2,2-trifluoroacetophenone with 68% ee13 while Takemoto et al. described a highly reactive α-Boc-amino MAHO that participated decarboxylative aldol reaction, and an adduct with the highest enantioselectivity of 90% ee was obtained when 2-nitrobenzaldehyde was employed as an electrophile.12 Thus, the efficient activation of unmodified, less active MAHOs with good enantiocontrol is still very challenging and in high demand. Herein, we report our preliminary research result on this topic (Figure 1c). A Ni(II)−oxazoline complex-promoted decarboxylative aldol reaction of simple MAHOs was developed, in which a wide range of carbonyls such as aldehydes, Phenylgly oxals, tryptanthrins, 2-acetylpyridines, α-keto amide, α-diketones, and isatins were all successfully employed as electrophiles and afforded desired products with good yields and enantioselectivities; it was shown that various unsaturated groups, even extra carbonyls on electrophiles, were well tolerated. Importantly, with this methodology, rapid access to optically active phenylpropanoid, phthalide, phaitanthrin B, 4-hydroxy5-phenyldihydrofuran-2(3H)-one, and an (R)-duloxetine intermediate was also achieved. Considering the great synthetic utility of β-aryl-β-hydroxy esters and pushed by our failure to employ aldehyde electrophiles in the synthesis of carboxylic acid,10 we started our studies by exploring a proper catalytic system for the decarboxylative aldol reaction of 4-nitrobenzaldehyde and 3methoxy-3-oxopropanoic acid. The reaction condition reported by shair’s group11c was first examined. Unfortunately, no desired product was observed within 24 h. Subsequently, a careful screening of metal salts was carried out, which revealed that Ni(OAc)2·4H2O was a good catalyst, affording the desired methyl 3-hydroxy-3-(4-nitrophenyl)propanoate 3a in 60% yield at 80 °C (Table 1, entry 1; for the full evaluation of metal salts, see the Supporting Information). With this catalyst in hand, the effects of different chiral ligands were next studied (entries 2−9). It was shown that an oxazoline L7-derived catalyst exhibited best catalytic activity and enantiocontrol, resulting in desired product 3a in 60% yield and 60% ee (entry 8). To improve the enantioselectivity, various solvents as well as reaction temperatures were subsequently evaluated (see the Supporting Information). However, the highest optical purity of 77% ee accompanied by a moderate yield was obtained when the reaction was carried out in THF at 20 °C with the promotion of anhydrous Ni(OAc)2 (entry 11). To further optimize reaction conditions, different nickel salts were fully evaluated. Unfortunately, some nickel catalysts failed to promote the reaction, probably because of their poor solubility in THF that caused the bad coordination with ligands (entry 12; full evaluation in the Supporting Information). These failures inspired us to systematically study the influence of anion species of nickel salts. Considering the limited nickel salts that are commercially available, an anion-exchange strategy was employed by simply mixing nickel salts with different acid salts before coordinating. For this purpose, different sodium salts of aliphatic or aromatic acids were

entry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21d 22d,e 23d,e,f 24d,e

additive (oNO2− PhCO2M)

t (°C/h)

yield (%)b

−

80/24

60

−

L1

−

80/12

45

2

L2

−

80/12

45

9

L3

−

80/12

27

9

L4

−

80/12

45

9

L5

−

80/12

56

1

L6

−

80/12

60

21

L7

−

80/12

60

60

L8

−

80/12

32

19

L7

−

20/24

49

77

L7 L7

− −

20/24 20/48

54 trace

77 −

L7 L7 L7 L7 L7 L7 L7 L7 L7 L7 L7 L7

Na Na Na Li K Rb Cs Mg K K K K

20/24 20/24 20/24 20/24 20/24 20/24 20/24 20/24 20/24 20/24 20/36 15/60

53 47 54 trace 56 54 54 trace 74 89 80 89

80 75 88 − 89 84 85 − 91 90 90 92

catalyst

ligand

Ni(OAc)2· 4H2O Ni(OAc)2· 4H2O Ni(OAc)2· 4H2O Ni(OAc)2· 4H2O Ni(OAc)2· 4H2O Ni(OAc)2· 4H2O Ni(OAc)2· 4H2O Ni(OAc)2· 4H2O Ni(OAc)2· 4H2O Ni(OAc)2· 4H2O Ni(OAc)2 NiX2 (X = F, Cl, or Br) Ni(OAc)2 NiCl2 NiCl2·6H2O NiCl2·6H2O NiCl2·6H2O NiCl2·6H2O NiCl2·6H2O NiCl2·6H2O NiCl2·6H2O NiCl2·6H2O NiCl2·6H2O NiCl2·6H2O

−

ee (%)c

a

General reaction conditions: 1 (0.2 mmol), 2 (0.4 mmol), ligand (22 mol %), additive (45 mol %), and catalyst (20 mol %) in 2 mL of solvent at a specific temperature. bIsolated yield. cDetermined by chiral HPLC analysis. do-NO2-PhCO2K (60 mol %) was used. eWith 100 mg of 5 Å molecular sieves. fNiCl2·6H2O (10 mol %) was used.

carefully examined under standard conditions (see the Supporting Information). Encouragingly, sodium 2-nitrobenzoate was proven to be the optimal additive that afforded desired product 3a in 80% ee (entry 13). With this information in hand, various nickel salts were investigated again in the presence of sodium 2-nitrobenzoate (see the Supporting Information). Interestingly, previously inactive NiCl2 exhibited good catalytic activity and enantiocontrol under modified conditions, while NiCl2·6H2O was found to be the best choice B

DOI: 10.1021/acs.orglett.9b02297 Org. Lett. XXXX, XXX, XXX−XXX

Letter

Organic Letters

substituted aldehydes were employed as electrophiles (3n− 3p, 3s, 3t, and 3ac), and the resulting β-hydroxy esters bearing an extra carbonyl group that cannot be obtained from traditional asymmetric hydrogenation reactions could be versatile chiral building blocks in enantioselective synthesis. In addition, the reaction between 2a and 2-thiophenecarboxaldehyde afforded an efficient way to construct the key intermediate of (R)-duloxetine 3af (76% yield, 94% ee). Importantly, 2-oxopropanal and aliphatic aldehydes that were capable of self-condensation were also smoothly converted into desired products 3ag−3ai in good yields and 80−93% ee. The absolute configurations of products in Scheme 1 were assigned by comparing their rotation values with literature data. Inspired by the good results obtained above and our ongoing interest in exploring new catalytic processes for the construction of enantioenriched indoloquinazoline alkaloids,10,14 we subsequently investigated the possibility of the asymmetric synthesis of phaitanthrin B15 and its derivatives via decarboxylative aldol reaction of tryptanthrin. To the best of our knowledge, there is no example exit for the direct catalytic construction of enantioenriched phaitanthrin B. However, very low enantioselectivity (19% ee) was obtained when the reaction of 2a and tryptanthrin was carried out under standard conditions. Fortunately, a careful evaluation of reaction conditions revealed that the desired product phaitanthrin B 5a can be obtained in excellent enantioselectivity with the promotion of the Ni(OAc)2−L1 complex in CH3CN (for the details of the evaluation conditions, see the Supporting Information). Encouraged by this result, we employed a variety of tryptanthrin derivatives as electrophiles under modified conditions. As shown in Scheme 2, different functional groups were well tolerated and good to excellent yields and optical purities were obtained in most cases (5a−5i, up to >99% ee). Subsequently, different MAHOs were also successfully employed in this reaction, affording the desired products in high enantioselectivities of up to >99% ee, albeit with lower yields (5j−5p). Additionally, this methodology was also compatible with various ketone type electrophiles under modified reaction conditions (for the details of evaluation conditions, see the Supporting Information). For example, 2acylpyridines and 2-oxo-N,2-diphenylacetamide reacted with 2a smoothly to afford corresponding β-hydroxy esters 5q−5s and 5v with a quaternary stereocenter in good enantioselectivities of 82−92% ee. In addition, isatins were also found to be good participants in this transformation. It was shown that the substituent group on the nitrogen or aromatic ring of isatin had little influence on the reactivity and enantiocontrol; free isatin, N-methyl isatin, and isatin with either electron-withdrawing or electron-donating group were all tolerated well and led to the desired products with good results (5w−5z). Additionally, αdiketones exhibited good reactivity and were converted into enantioenriched γ-carbonyl β-hydroxy esters (5t and 5u) with high yields and 92%−98% ee in 12 h. Noticeably, when 1Hindene-1,2(3H)-dione was employed as an electrophile, excellent regioselectivity and enantioselectivity were observed (5t), and the catalyst loading can be decreased to 0.5 mol % without a loss of yield or enantioselectivity (72 h, 90%, 98% ee). The absolute configuration of product 5a was assigned by comparing its rotation value with our previous report.10 To demonstrate synthetic utilities of our methodology with enantioenriched β-hydroxy esters, a two-step synthesis of phenylpropanoid,3a,16 which was isolated from Peperomia tetraphylla with cytotoxicity against the A549, HeLa, and

for a catalyst (entry 15, 88% ee). Further optimizations of reaction conditions revealed that the cation types of acid salts, molecular sieves (M.S.), and temperature had obvious influences on the result (entries 15−24). For example, 60 mol % potassium 2-nitrobenzoate was found to be necessary to improve the catalytic ability as well as enantiocontrol. Finally, the best result was obtained when the reaction was catalyzed by a NiCl2·6H2O−L7 complex in the presence of 60 mol % potassium 2-nitrobenzoate and 5 Å M.S. at 15 °C (entry 24, 89%, 92% ee). Using the conditions described in Table 1, the generality of the protocol was first demonstrated by evaluating a variety of MAHOs with 4-nitrobenzaldehyde 1a. As shown in Scheme 1, Scheme 1. Catalytic Asymmetric Decarboxylative Addition of Malonic Acid Half-Oxyesters and Aldehydesa,b

a

General reaction conditions: 1 (0.2 mmol), 2a (0.4 mmol), ligand (22 mol %), catalyst (20 mol %), o-NO2-PhCO2K (60 mol %), and 100 mg of 5 Å molecular sieves in 2 mL of THF at the corresponding temperature for a specific time; isolated yield; determined by chiral HPLC analysis. bAt 15 °C for 96 h. cAt 30 °C for 120 h. dAt 20 °C for 144 h. eAt 50 °C for 48 h. fAt −40 °C for 144 h. gWith 10 mol % catalyst. hAt 25 °C for 48 h. iWith 5 mol % catalyst. jIn THP (tetrahydropyran) at 30 °C for 36 h and then at 80 °C for 16 h.

MAHOs with different ester groups all result in desired products with good yield and enantioselectivity (3a−3f). In addition, other decarboxylative candidates were also tested. Encouragingly, 2-cyanoacetic acid reacted smoothly with 1a under standard reaction conditions, affording the desired product with good yield and moderate enantioselectivity (3g). Subsequently, the expansion of the protocol to a variety of aromatic aldehydes was also proven to be successful, and high enantioselectivities were achieved with either electron-donating or electron-withdrawing substituents under standard reaction conditions (24 examples, ≤94% ee). It was shown that carbonyls, cyano, and double and triple bonds on the aromatic ring were well tolerated and afforded the desired product in good to excellent enantioselectivity (3n−3p, 3s, 3t, 3x, 3ac, 3ad, and 3ag). Noticeably, good chemoselectivities were observed even when cyano-, formyl-, or benzoylC

DOI: 10.1021/acs.orglett.9b02297 Org. Lett. XXXX, XXX, XXX−XXX

Letter

Organic Letters Scheme 2. Catalytic Asymmetric Decarboxylative Addition of Malonic Acid Half-Oxyesters and Ketonesa

Scheme 4. Asymmetric Synthesis of 3-Hydroxyl ButyrolActone and Phthalide Derivatives

phenylbutanoate 3ad could be reduced by NaBH4 in MeOH, producing chiral 4-hydroxy-5-phenyldihydrofuran-2(3H)-one, the key structure of juglomycin A and B, in good yield and optical purity. In addition, methyl 2-formylbenzoate could proceed via a decarboxylative aldol-transesterification cascade with 2a under standard conditions and afforded methyl 2-(3oxo-1,3-dihydroisobenzofuran-1-yl)acetate, an analogue of soochracinic acid II and herbaric acid III, in moderate yield and enantioselectivity.17 To demonstrate the synthetic utility of our protocol, a 1 mmol-scale catalytic procedure was performed. As shown in Scheme 5, by treatment of 1H-indene-1,2(3H)-dione (1 Scheme 5. One Millimole-Scale Catalytic Procedure a

General reaction conditions: 2 (0.4 mmol), 4 (0.2 mmol), ligand L1 (22 mol %), catalyst Ni(OAc)2 (20 mol %) in 2 mL of CH3CN at the corresponding temperature for a specific time; isolated yield; determined by chiral HPLC analysis. bNiF2·4H2O (20 mol %), L7 (25 mol %), 50 mg of 5 Å molecular sieves in 2 mL of THF under a nitrogen atmosphere at 10 °C for 48 h. cNi(OAc)2·4H2O (5 mol %), L5 (6 mol %) in 2 mL of CPME (cyclopentyl methyl ether) at 10 °C for 12 h. dNi(OAc)2·4H2O (10 mol %), L5 (11 mol %) in 2 mL of THF at 10 °C for 12 h. eNiCl2·6H2O (10 mol %), L6 (11 mol %) and o-NO2-PhCO2K (60 mol %) in 2 mL of CPME at 25 °C for 96 h. f NiCl2·6H2O (10 mol %), L6 (11 mol %) in 2 mL of THF at 10 °C for 96 h. gNiCl2·6H2O (10 mol %), L6 (11 mol %) in 2 mL of THP at 10 °C for 96 h.

mmol) with 2a (2 mmol) in the promotion of 0.5 mol % catalyst, desired product 5t was obtained in high yield and enantioselectivity (88% yield, 98% ee). On the basis of the results presented above, a nickelcatalyzed aldol-decarboxylation mechanism was proposed. As shown in Figure 2, a nickel−MAHO complex was first formed by interaction of the chiral nickel complex and MAHO; subsequently, enolization and deprotonation of the nickel− MAHO complex generated a nucleophilic intermediate II, which was capable of enantioselectively attacking aldehydes/

HepG2 cell lines, was first carried out. As shown in Scheme 3, commercially available myristicin aldehyde can be smoothly Scheme 3. Asymmetric Synthesis of Phenylpropanoid

converted into corresponding β-hydroxy ester ent-3y in 71% yield and 90% ee under standard conditions; subsequently, treatment of ent-3y with a simple esterification afforded phenylpropanoid in 67% overall yield and 90% ee. In addition, the high functional group tolerance of this method also allowed further transformations to access diverse valuable chiral building blocks such as 3-hydroxyl butyrolactone and phthalide with simple operations (Scheme 4), which are wildly found in many bioactive natural products. For example, enantioenriched product methyl 3-hydroxy-4-oxo-4-

Figure 2. Proposed mechanism of the aldol-decarboxylation reaction. D

DOI: 10.1021/acs.orglett.9b02297 Org. Lett. XXXX, XXX, XXX−XXX

Letter

Organic Letters

configurations and pharmacological activities of the optical isomers of fluoxetine, a selective serotonin-uptake inhibitor. J. Med. Chem. 1988, 31, 1412−1417. (4) (a) Norman, T. R.; Olver, J. S. Continuation treatment of major depressive disorder: is there a case for duloxetine. Drug Des., Dev. Ther. 2010, 4, 19−31. (b) Bymaster, F. P.; Beedle, E. E.; Findlay, J.; Gallagher, P. T.; Krushinski, J. H.; Mitchell, S.; Robertson, D. W.; Thompson, D. C.; Wallace, L.; Wong, D. T. Duloxetine (Cymbalta), a dual inhibitor of serotonin and norepinephrine reuptake. Bioorg. Med. Chem. Lett. 2003, 13, 4477−4480. (5) Cashman, J. R.; Ghirmai, S. Inhibition of serotonin and norepinephrine reuptake and inhibition of phosphodiesterase by multi-target inhibitors as potential agents for depression. Bioorg. Med. Chem. 2009, 17, 6890−6897. (6) Wee, S.; Woolverton, W. L. Evaluation of the reinforcing effects of atomoxetine in monkeys: comparison to methylphenidate and desipramine. Drug Alcohol Depend. 2004, 75, 271−276. (7) (a) Hu, A.; Ngo, H. L.; Lin, W. Chiral, Porous, Hybrid Solids for Highly Enantioselective Heterogeneous Asymmetric Hydrogenation of β-Keto Esters. Angew. Chem., Int. Ed. 2003, 42, 6000−6003. (b) Hu, A.; Ngo, H. L.; Lin, W. Remarkable 4,4′-Substituent Effects on Binap: Highly Enantioselective Ru Catalysts for Asymmetric Hydrogenation of β-Aryl Ketoesters and Their Immobilization in Room-Temperature Ionic Liquids. Angew. Chem., Int. Ed. 2004, 43, 2501−2504. (c) Ma, B.; Miao, T.; Sun, Y.; He, Y.; Liu, J.; Feng, Y.; Chen, H.; Fan, Q.-H. A New Class of Tunable Dendritic Diphosphine Ligands: Synthesis and Applications in the Ru-Catalyzed Asymmetric Hydrogenation of Functionalized Ketones. Chem. - Eur. J. 2014, 20, 9969−9978. (d) Jeulin, S.; Duprat de Paule, S.; RatovelomananaVidal, V.; Genet, J.-P.; Champion, N.; Dellis, P. Difluorphos, an Electron-Poor Diphosphane: A Good Match Between Electronic and Steric Features. Angew. Chem., Int. Ed. 2004, 43, 320−325. (e) Jeulin, S.; de Paule, S. D.; Ratovelomanana-Vidal, V.; Genet, J.-P.; Champion, N.; Dellis, P. Chiral biphenyl diphosphines for asymmetric catalysis: Stereoelectronic design and industrial perspectives. Proc. Natl. Acad. Sci. U. S. A. 2004, 101, 5799−5804. (f) Sun, X.; Li, W.; Hou, G.; Zhou, L.; Zhang, X. Axial Chirality Control by 2,4Pentanediol for the Alternative Synthesis of C3*-TunePhos Chiral Diphosphine Ligands and Their Applications in Highly Enantioselective Ruthenium-Catalyzed Hydrogenation of β-Keto Esters. Adv. Synth. Catal. 2009, 351, 2553−2557. (g) Wan, X.; Sun, Y.; Luo, Y.; Li, D.; Zhang, Z. Synthesis of a Bulky and Electron-Rich Derivative of SEGPhos and Its Application in Ru-Catalyzed Enantioselective Hydrogenation of β-Ketoesters. J. Org. Chem. 2005, 70, 1070−1072. (h) Qiu, L.; Kwong, F. Y.; Wu, J.; Lam, W. H.; Chan, S.; Yu, W.-Y.; Li, Y.-M.; Guo, R.; Zhou, Z.; Chan, A. S. C. A New Class of Versatile Chiral-Bridged Atropisomeric Diphosphine Ligands: Remarkably Efficient Ligand Syntheses and Their Applications in Highly Enantioselective Hydrogenation Reactions. J. Am. Chem. Soc. 2006, 128, 5955−5965. (i) Qiu, L.; Wu, J.; Chan, S.; Au-Yeung, T.; Ji, J.-X.; Guo, R.; Pai, C.-C.; Zhou, Z.; Li, X.; Fan, Q.-H.; Chan, A. S. C. Remarkably diastereoselective synthesis of a chiral biphenyl diphosphine ligand and its application in asymmetric hydrogenation. Proc. Natl. Acad. Sci. U. S. A. 2004, 101, 5815−5820. (j) Ireland, T.; Grossheimann, G.; Wieser-Jeunesse, C.; Knochel, P. Ferrocenyl Ligands with Two Phosphanyl Substituents in the α,ε positions for the Transition Metal Catalyzed Asymmetric Hydrogenation of Functionalized Double Bonds. Angew. Chem., Int. Ed. 1999, 38, 3212−3215. (k) Lotz, M.; Polborn, K.; Knochel, P. New Ferrocenyl Ligands with Broad Applications in Asymmetric Catalysis. Angew. Chem., Int. Ed. 2002, 41, 4708−4711. (l) Fukuzawa, S.-I.; Oki, H.; Hosaka, M.; Sugasawa, J.; Kikuchi, S. ClickFerrophos: New Chiral Ferrocenyl Phosphine Ligands Synthesized by Click Chemistry and the Use of Their Metal Complexes as Catalysts for Asymmetric Hydrogenation and Allylic Substitution. Org. Lett. 2007, 9, 5557− 5560. (8) (a) Narasaka, K.; Soai, K.; Mukaiyama, T. The New Michael Reaction. Chem. Lett. 1974, 3, 1223−1224. (b) Narasaka, K.; Soai, K.; Aikawa, Y.; Mukaiyama, T. The Michael Reaction of Silyl Enol Ethers

ketone acceptors and afforded an aldol type adduct with great structural diversity. Finally, resulting adduct V cleaved CO2 to produce the desired β-hydroxy ester in an enantioenriched form. In conclusion, we developed a general and efficient method for the direct construction of optically active β-hydroxy esters under the potassium 2-nitrobenzoate-assisted Ni−oxazoline complex catalysis. Various functional groups, including active carbonyls, were well tolerated and enabled the rapid access to a series of β-hydroxy esters with great structural diversity. Importantly, this methodology can be conveniently employed in the construction of enantioenriched phenylpropanoid, phthalide, and 4-hydroxy-5-phenyldihydrofuran-2(3H)-one. We anticipate that this promising strategy could be next applied to the synthesis of versatile β-substituted esters in our laboratory.

■

ASSOCIATED CONTENT

S Supporting Information *

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.orglett.9b02297. Experimental procedures, characterization, and NMR spectra of new compounds (PDF) Accession Codes

CCDC 1878656 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif, or by emailing [email protected], or by contacting The Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44 1223 336033.

■

AUTHOR INFORMATION

Corresponding Authors

*E-mail: [email protected]. *E-mail: [email protected]. ORCID

Hongxin Liu: 0000-0001-5401-2953 Jun Jiang: 0000-0001-5815-1600 Notes

The authors declare no competing financial interest.

■

ACKNOWLEDGMENTS The authors gratefully acknowledge the National Natural Science Foundation of China (21472141 and 21571144), the Zhejiang Provincial Natural Science Foundation of China (LY18B020011 and LQ19B020004), and the Foundation of Zhejiang Educational Committee (Y201430852 and Y201839490).

■

REFERENCES

(1) Andrushko, N.; Andrushko, V. Asymmetric Hydrogenation of C O and CN Bonds in Stereoselective Synthesis. Stereoselective Synthesis of Drugs and Natural Products; Wiley: Hoboken, NJ, 2013; pp 909− 959. (2) Nakamura, S.; Takeuchi, T.; Hori, S.; Matsuzaki, M.; Umezawa, H. Phenomycin, toxicity and distribution. J. Antibiot. 1971, 24, 197− 199. (3) (a) Seigler, D.; Phenylpropanoids, S. Plant Secondary Metabolism; Springer: New York, 1998; pp 106−129. (b) Robertson, D. W.; Krushinski, J. H.; Fuller, R. W.; Leander, J. D. The absolute E

DOI: 10.1021/acs.orglett.9b02297 Org. Lett. XXXX, XXX, XXX−XXX

Letter

Organic Letters with α,β-Unsaturated Eetones and Acetals in the Presence of Titanium Tetraalkoxide and Titanium Tetrachloride. Bull. Chem. Soc. Jpn. 1976, 49, 779−783. (c) Kobayashi, S.; Manabe, K. Development of Novel Lewis Acid Catalysts for Selective Organic Reactions in Aqueous Media. Acc. Chem. Res. 2002, 35, 209−217. (9) Zhang, X.-M.; Bordwell, F. G.; Van der Puy, M.; Fried, H. E. Equilibrium acidities and homolytic bond dissociation energies of the acidic carbon-hydrogen bonds in N-substituted trimethylammonium and pyridinium cations. J. Org. Chem. 1993, 58, 3060−3066. (10) Gao, H.; Luo, Z.; Ge, P.; He, J.; Zhou, F.; Zheng, P.; Jiang, J. Direct Catalytic Asymmetric Synthesis of β-Hydroxy Acids from Malonic Acid. Org. Lett. 2015, 17, 5962−5965. In this research, attempts to employ other electrophiles such as aldehydes were all failed. (11) (a) Nakamura, S. Catalytic enantioselective decarboxylative reactions using organocatalysts. Org. Biomol. Chem. 2014, 12, 394− 405. (b) Wang, Z.-L. Recent Advances in Catalytic Asymmetric Decarboxylative Addition Reactions. Adv. Synth. Catal. 2013, 355, 2745−2755. (c) Magdziak, D.; Lalic, G.; Lee, H. M.; Fortner, K. C.; Aloise, A. D.; Shair, M. D. Catalytic Enantioselective Thioester Aldol Reactions That Are Compatible with Protic Functional Groups. J. Am. Chem. Soc. 2005, 127, 7284−7285. (d) Fortner, K. C.; Shair, M. D. Stereoelectronic Effects Dictate Mechanistic Dichotomy between Cu(II)-Catalyzed and Enzyme-Catalyzed Reactions of Malonic Acid Half Thioesters. J. Am. Chem. Soc. 2007, 129, 1032−1033. (e) Hara, N.; Nakamura, S.; Funahashi, Y.; Shibata, N. Organocatalytic Enantioselective Decarboxylative Addition of Malonic Acids Half Thioesters to Isatins. Adv. Synth. Catal. 2011, 353, 2976−2980. (f) Zhong, F. R.; Yao, W. J.; Dou, X. W.; Lu, Y. X. Enantioselective Construction of 3-Hydroxy Oxindoles via Decarboxylative Addition of β-Ketoacids to Isatins. Org. Lett. 2012, 14, 4018−4021. (g) Zheng, Y.; Xiong, H. Y.; Nie, J.; Hua, M. Q.; Ma, J. A. Biomimetic catalytic enantioselective decarboxylative aldol reaction of β-ketoacids with trifluoromethyl ketones. Chem. Commun. 2012, 48, 4308−4310. (h) Hara, N.; Nakamura, S.; Sano, M.; Tamura, R.; Funahashi, Y.; Shibata, N. Enantioselective Synthesis of AG-041R by using NHeteroarenesulfonyl Cinchona Alkaloid Amides as Organocatalysts. Chem. - Eur. J. 2012, 18, 9276−9280. (i) Yin, L.; Kanai, M.; Shibasaki, M. Cu(I)-catalyzed decarboxylative aldol-type and Mannich-type reactions for asymmetric construction of contiguous trisubstituted and quaternary stereocenters. Tetrahedron 2012, 68, 3497−3506. (j) Bae, H. Y.; Sim, J. H.; Lee, J.-W.; List, B.; Song, C. E. Organocatalytic Enantioselective Decarboxylative Aldol Reaction of Malonic Acid Half Thioesters with Aldehydes. Angew. Chem., Int. Ed. 2013, 52, 12143− 12147. (k) Wei, A.-J.; Nie, J.; Zheng, Y.; Ma, J.-A. Ni-Catalyzed Highly Chemo-, Regio-, and Enantioselective Decarboxylative Aldol Reaction of β,γ-Unsaturated α-Ketoesters with β-Ketoacids. J. Org. Chem. 2015, 80, 3766−3776. (12) March, T.; Murata, A.; Kobayashi, Y.; Takemoto, Y. Enantioselective Synthesis of anti-β-Hydroxy-α-amino Esters via an Organocatalyzed Decarboxylative Aldol Reaction. Synlett 2017, 28, 1295−1299. (13) Li, X.-J.; Xiong, H.-Y.; Hua, M.-Q.; Nie, J.; Zheng, Y.; Ma, J.-A. Convenient and efficient decarboxylative aldol reaction of malonic acid half esters with trifluoromethyl ketones. Tetrahedron Lett. 2012, 53, 2117−2120. (14) Kang, G.; Luo, Z.; Liu, C.; Gao, H.; Wu, Q.; Wu, H.; Jiang, J. Amino Acid Salts Catalyzed Asymmetric Aldol Reaction of Tryptanthrin: A Straightforward Synthesis of Phaitanthrin A and Its Derivatives. Org. Lett. 2013, 15, 4738−4741. (15) Jao, C.-W.; Lin, W.-C.; Wu, Y.-T.; Wu, P.-L. Isolation, Structure Elucidation, and Synthesis of Cytotoxic Tryptanthrin Analogues from Phaius mishmensis. J. Nat. Prod. 2008, 71, 1275−1280. (16) Yu, Y.; Lu, X.; Wu, W.; Wu, Y.; Liu, B. Absolute Configuration of the Phenylpropanoid Isolated from Peperomia tetraphylla. Chin. J. Chem. 2013, 31, 1336−1340. (17) (a) Santana, M. D.; García, G.; López, G.; Lozano, A.; Vicente, C.; García, L.; Pérez, J. Preparation, crystal structures and NMR characterization of substituted-benzoate complexes Nickel(II)-N3-

macrocycles. Polyhedron 2007, 26, 1029−1036. (b) Liu, B.-X.; Chen, G.-H.; Lin, Y.-Y.; Yu, Y.-P. Bis(2,2′-diamino-4,4′-bi-1,3-thiazole -κ2N,N′)(2-nitrobenzoato-κ2O,O′) nickel(II) 2-nitrobenzoate. Acta Crystallogr., Sect. E: Struct. Rep. Online 2007, E63, m1971.

F

DOI: 10.1021/acs.orglett.9b02297 Org. Lett. XXXX, XXX, XXX−XXX