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Asymmetric Decarboxylative Cycloaddition of Vinylethylene Carbonates with #-Nitroolefins by Cooperative Catalysis of Palladium Complex and Squaramide Ke Liu, IJAZ KHAN, Jiong Cheng, Yu Jen Hsueh, and Yong Jian Zhang ACS Catal., Just Accepted Manuscript • DOI: 10.1021/acscatal.8b03582 • Publication Date (Web): 02 Nov 2018 Downloaded from http://pubs.acs.org on November 2, 2018
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ACS Catalysis
Asymmetric Decarboxylative Cycloaddition of Vinylethylene Carbonates with β-Nitroolefins by Cooperative Catalysis of Palladium Complex and Squaramide Ke Liu, Ijaz Khan, Jiong Cheng, Yu Jen Hsueh and Yong Jian Zhang* School of Chemistry and Chemical Engineering, and Shanghai Key Laboratory of Electrical Insulation and Thermal Aging, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, P. R. China KEYWORDS: asymmetric catalysis, cooperative catalysis, palladium catalysis, chiral squaramide, multisubstituted tetrahydrofurans, cycloaddition
ABSTRACT: An efficient method for the enantio- and diastereoselective construction of mutisubstituted tetrahydrofurans via asymmetric decarboxylative cycloaddition of vinylethylene carbonates with β-nitroolefins under cooperative catalysis system of palladium complex and squaramide is developed. By using a palladium complex generated in situ from Pd2(dba)3•CHCl3 and phosphoramidite L1 and chiral squaramide OC4 as cooperative catalysts under mild conditions, the process provided multisubstituted tetrahydrofurans bearing a quaternary stereocenter in good to high yields with acceptably high enantio- and diastereoselectivities.
Since the first report on the cycloaddition using palladiumtrimethylenemethane (TMM) complex as a 1,3-dipole with electron-deficient olefins by Trost and Chan in 1979,1 the Pdcatalyzed cycloaddition reactions through zwitterionic allylpalladium intermediates have been extensively investigated for the construction of various cyclic frameworks.2 Various allylic donors have successfully been applied for this transformation with diverse unsaturated electrophiles. Among them, vinyl epoxides have served as efficient C,O-dipoles in the Pd-catalyzed cycloaddition reactions to afford oxo-cyclic compounds.3,4 However, the process mostly limited to butadiene oxide and isoprene oxide, and the asymmetric variants are largely underdeveloped.5 Most recently, we developed vinylethylene carbonates (VECs) as more stable and readily accessible allylic donors and achieved the Pd-catalyzed asymmetric decarboxylative cycloaddition of VECs with various unsaturated electrophiles to afford diverse heterocycles with tetrasubstituted stereocenters in high efficiencies.6 Very recently, using VECs as 1,5-dipoles for the cycloaddition reactions have also been reported to construct medium-sized oxo-cyclic compounds.7 Both vinylepoxides and VECs give zwitterionic allylpalladium intermediates I with a palladium catalyst (Scheme 1). The πallyl species I attacks unsaturated electrophiles and followed by cycloaddition to afford desired products A. However, if the electrophilicity of the electrophiles are not strong enough, the π-allyl species I would undergo β-hydride elimination and isomerization to form α,β-unsaturated aldehydes B as byproducts.8 This might be a reason that double activated Michael acceptors are needed for the cycloaddition reaction with electron deficient alkenes.5d,e,6a,g Hou and co-workers
reported Pd-catalyzed asymmetric cycloaddition of vinyl epoxides with mono-activated Scheme 1. Cycloaddition of vinylepoxides or VECs with unsaturated electrophiles O O
or O
R
Pd
O
O
Pd R
R
E
Nu
O
O
E Nu H R A
I
R B
Scheme 2. Cooperative catalysis strategy cycloaddition of VECs with β-nitroolefins O N O
R' O O
O
Pd-L*
L* Pd
O
R1 H N H N R2
O O
O O
R2 N H
N H R1
O
R
the
O N R'
R 1
for
L* Pd O II
I R' O * * * R 3
R
NO2
nitroalkenes,5e but the enantioselectivity was lower. Most recently, they reported the asymmetric cycloaddition of vinyl epoxides with α,β-unsaturated ketones to provide multisubstituted tetrahydrofurans with high stereoselectivity.5c However, large excess of vinyl epoxides (4 equiv.) and long reaction time (5 days) were needed for the process. Therefore,
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the development of efficient methods for the cycloaddition reaction of VECs with single activated Michael acceptors is also highly appealing. Table 1. Condition optimizationsa Pd2(dba)3 . CHCl3 (2.5 mol%) ligand (10 mol%) organocatalyst (20 mol%)
O O
O
+ Ph
NO2
Ph 1a
O R P N R O
O Ar
N H
O P N O
O H Ph 4a
Ph 3aa
O O
L4
NO2
O
4 Å MS solvent, 20 oC, 42 h
2a
L1 R = iPr L2 R = (R)-1-phenylethyl L3 R = (S)-1-phenylethyl
Ph
O P N O
P N
L5
L6
O O OC1, Ar = 3,5-di-CF3C6H3; R = Me OC2, Ar = 4-CF3C6H4; R = Me Ar Ar OC3, Ar = 3,5-di-CF3C6H3; R,R = -(CH2)5N N N H H OC4, Ar = 4-CF3C6H4; R,R = -(CH2)5H N OC6, Ar = 4-CF3C6H4 R R OC5, Ar = 4-OMeC6H4; R,R = -(CH2)5-
O
entr y
liga nd
OC
solvent
yield (%) of 3aab
ee (%)c
drd
1
L1
-
THF
70
75
>20:1
2
L2
-
THF
59
17
>20:1
3
L3
-
THF
73
21
>20:1
4
L4
-
THF
36
70
>20:1
5
L5
-
THF
47
3
>20:1
6
L1
OC1
THF
42
77
10:1
7
L1
OC2
THF
51
80
>20:1
8
L1
OC3
THF
NR
-
-
9
L1
OC4
THF
63
83
20:1
10
L1
OC5
THF
48
71
>20:1
11
L6
OC4
THF
59
2
13:1
12
L1
OC4
toluene
73
92
14:1
13
L1
OC4
CH2Cl2
71
93
4:1
14
L1
OC4
CyH
NR
-
-
15
L1
OC4
dioxane
63
90
18:1
16
L1
OC4
MTBE
70
94
13:1
17
L1
OC4
DME
62
83
20:1
18
L1
OC4
CH3CN
34
37
8:1
19
L1
OC4
Et2O
74
95
14:1
20
L1
entOC4
Et2O
71
90
10:1
21
entL1
OC4
Et2O
64
-92
12:1
22
entL1
entOC4
Et2O
75
-95
14:1
23
L1
OC6
Et2O
46
75
6:1
24
L1
-
Et2O
67
91
>20:1
25
racL1
OC4
Et2O
61
1
9:1
a Reaction conditions: Pd (dba) •CHCl (2.5 mol%), ligand (10 2 3 3 mol%), organocatalyst (20 mol%), 1a (0.3 mmol), 2a (0.2 mmol), 4 Ǻ molecular sieves (50 mg), solvent (0.4 mL), 20 oC, 42 h. b Isolated yields for the mixture of the diastereomers. c Determined by HPLC using a chiral stationary phase. The absolute configuration was confirmed by X-ray crystallography of 5 (see Scheme 3). d Determined by 1H NMR spectroscopy of the crude reaction mixture.
Nitroolefins as important Michael acceptors have been applied in the asymmetric conjugated addition to construct highly functionalized chiral building blocks.9 For the catalytic asymmetric Michael addition to nitroolefins, hydrogenbonding catalysts, especially chiral squaramides,10 have recently emerged as an important strategy due to their ability to form stronger hydrogen bonds with nitro group. Inspired by this organic catalytic strategy, we are interested in the development of cooperative catalysis system11 using palladium complex and squaramide to achieve the decarboxylative cycloaddition of VECs with nitroolefins. Since the pioneer works by Gong12 and Takemoto13 respectively for the allylic substitution under cooperative catalysis system of palladium complex and chiral phase-transfer catalyst, the asymmetric allylic substitution catalyzed by synergetic transition metal and organocatalyst has recently attracted a great deal of attention.11 However, there have been no reports on the combination of transition-metal and squaramide for the allylic alkylation.14 We envisioned that the oxa-Michael addition of the zwitterionic allylpalladium intermediates I to nitroolefins could be realized by the squaramide activation to generate intermediate II (Scheme 2). The subsequent cycloaddition could occur to form desired products 3, and the stereochemistry could be controlled by the synergistic effect on chiral ligand and chiral squaramide. Herein, we report the asymmetric decarboxylative cycloaddition of VECs with βnitroolefins under cooperative catalysis system of palladium complex and squaramide to construct highly functionalized tetrahydrofurans with high absolute and relative stereocontrol. Initial studies focused on the decarboxylative cycloaddition of Ph-VEC 1a with (E)-β-nitrostyrene 2a as standard reaction partners. Based on our previous research results on the cycloaddition of VECs, we began our investigation by examining the cycloaddition of 1a (1.5 equiv.) with 2a (1.0 equiv.) in the presence of a Pd(0)-catalyst bearing different phosphoramidite ligands (Table 1). The reactions using phosphoramidites15 derived from binol proceeded to give desired product 3aa along with α,β-unsaturated aldehyde 4a as a byproduct (entries 1-3). The reaction with phosphoramidite L1 bearing diisopropylamino group revealed best results to afford cycloadduct 3aa in 70% yield with 75% ee and excellent diastereoselectivity (entry 1). The reaction could not improve by using the ligand L4 and L516 (entries 4 and 5). Next, we tried to investigate the reaction by the combination with chiral squaramide17 as a co-catalyst (entries 6-10). To our delight, the enantioselectivity could be improved to 83% ee by using Pd-catalyst with ligand L1 and chiral squaramide OC4 (entry 9). When the reaction was conducted in the presence of Pd-complex with achiral phosphoramidite L6 and chiral squaramide OC4, almost racemic product was obtained (entry 11). With the combination of ligand L1 and squaramide OC4, the process was examined in other solvents (entries 12-19). As the results, we found that the reaction in diethyl ether gave best results, providing the cycloadduct 3aa in 74% yield with 95% ee (entry 19), even though the diastereoselectivity was
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ACS Catalysis slightly decreased (14:1). With these optimal conditions in hand, we tried to investigate the influence of the absolute configuration of the ligand L1 and squaramide OC4 on the reaction performance (entries 19-22). When the reaction was catalyzed by Table 2. Substrate scope for the asymmetric decarboxylative cycloaddition of VECs 1 with nitroolefins 2 Pd2(dba)3 . CHCl3 (2.5 mol%) L1 (10 mol%) OC4 (20 mol%)
O O
O
+
R'
NO2
R 1
2 Me
4 Å MS Et2O, 20 oC, 42 h Br
NO2 Ph 3aa 74% yield 14:1 d.r.; 95% ee
NO2
O R 3 CF3
NO2
NO2
O
O
R'
NO2
O
Ph 3ab 65% yield 17:1 d.r.; 93% ee
O
Ph 3ac 71% yield >20:1 d.r.; 94% ee
Ph 3ad 50% yield 10:1 d.r.; 90% ee S
O
S
NO2 O
NO2
Ph 3ae 52% yield 8:1 d.r.; 93% ee
NO2 O
O Ph 3af 74% yield 6:1 d.r.; 98% ee
Ph 3ag 79% yield 4:1 d.r.; 97% ee
Ph
Ph 3ah 71% yield 10:1 d.r.; 98% ee Ph NO2 O
8
NO2 O
NO2
O
Ph 3ai 90% yield 6:1 d.r.; 92% ee Ph NO2 O
OMe 3ca 63% yield 3:1 d.r.; 86% ee NO2
O
NO2 O
Ph 3aj 81% yield 7:1 d.r.; 90% ee Ph NO2
Ph 3ak 82% yield 7:1 d.r.; 80% ee Ph NO2 O
O
Ph
NO2 O
F 3da 52% yield 13:1 d.r.; 96% ee Ph NO2 O
Ph
NO2
O
Cl 3ea 62% yield 16:1 d.r.; 88% ee Ph
Me 3ba 70% yield 7:1 d.r.; 92% ee
NO2
O
Br 3fa 57% yield >20:1 d.r.; 92% ee Ph
NO2
O
F F
3ga 58% yield >20:1 d.r.; 95% ee
Cl
Cl
3ha 61% yield >20:1 d.r.; 94% ee
O
3ia 72% yield 20:1 d.r.; 97% ee
S 3ja 74% yield 17:1 d.r.; 96% ee
a Reaction conditions: Pd (dba) •CHCl (2.5 mol%), L1 (10 2 3 3 mol%), OC4 (20 mol%), 1a (0.3 mmol), 2a (0.2 mmol), 4 Ǻ molecular sieves (50 mg), Et2O (0.4 mL), 20 oC, 42 h. Yields are of isolated materials for the mixture of the diastereomers. The ee values were determined by HPLC using chiral stationary phase. The absolute configuration was confirmed by X-ray crystallography of 5 (see Scheme 3). Those of the other products were assigned by analogy. The diastereomeric ratios were determined by 1H NMR spectroscopy of the crude reaction mixture.
(S,S)-OC4, the cycloadduct ent-3aa with the opposite configuration was obtained (entries 21 and 22), and the reaction with combination of (R)-L1 and (S,S)-OC4 showed better yield and stereoselectivity (entry 22). Notably, all of the four reactions (entries 19-22) only gave two diastereomers with indicated dr ratios, and no other diastereomers were found in the reaction mixture. However, the yield and stereoselectivity were decreased remarkably while the reaction performed in the presence of chiral ligand L1 and achiral squaramide OC6 (entry 23). When the reaction conducted with L1 without chiral squaramide OC4 in diethyl ether, the yield and enantioselectivty were slightly decreased (entry 24). Almost racemic product with worse diastereoselectivity was obtained when the reaction proceeded in the presence of racemic ligand L1 and the chiral OC4 (entry 25). These results indicated that the stereochemistry of the reaction depends on the chirality of the ligand and squaramide, and there is matching/mismatching effect of the ligand and squaramide on the reaction efficiency. The reaction likely undergoes reversible Michael addition and a subsequent stereochemistry-determining cycloaddition to form a thermodynamically stable product. With the optimal conditions in hand, the generality of this protocol was evaluated firstly by the reaction of Ph-VEC 1a with various (E)-β-nitroolefins 2. As shown in Table 2, the reactions with (E)-β-nitrostyrenes bearing different electronic nature proceeded quite well to afford corresponding cycloadducts 3 in good yields with high enantio- and diastereoselectivities. The versatile heterocycles can also be installed by the reaction of 1a with 2-furanyl or thiophenyl nitroethenes to furnish cycloadducts 3af-3ah in good yields with high enantioselectivities and good diastereoselectivities. 2-alkyl substituted nitroethenes were also suitable substrates for the reaction give tetrahydrofurans 3ai-3ak in high yields with good to high enantioselectivities and good diastereoselectivities. Next, we examined that the reactions of various 4-substituted VECs 1 with (E)-β-nitrostyrene 2a. Various substituted aryl VECs having different electronic and steric properties were converted into the corresponding mutisubstituted tetrahydrofurans 3ba-3ha in good yields with good to high enantio- and diastereoselectivities. The reactions of VECs with 4-furanyl or thiophenyl groups also proceeded smoothly to afford cycloadducts 3ia and 3ja in high yields with high level of stereoselectivities. Notably, the excessed VECs converted into the corresponding (E)-α,β–unsaturated aldehydes 4 for all of the examples. It should be noted that the reaction of 4-alkyl-substituted VECs or H-VEC were not effective in this reaction conditions. Scheme 3. Gram-scale transformation and elaboration of 3aa
Pd-complex with (S)-L1 and (S,S)-OC4, the product 3aa was obtained with slightly lower yields and stereoselectivity (entries 20 versus 19). Correspondingly, when the reaction was conducted in the presence of (R)-L1 with (R,R)-OC4 or
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1a (6 mmol) + 2a (4 mmol)
Pd2(dba)3 . CHCl3 (2.5 mol%) L1 (10 mol%) OC4 (20 mol%) 4 Å MS Et2O, 20 oC, 72 h
Ph
NO2
Ph
NH
O Ph 3aa
0.94 g 80% yield 12:1 d.r.; 93% ee
55%
O Ph 6
Ts N
Ph
Grubbs 1st 97%
O Ph 7
The synthetic versatility of the present protocol was demonstrated by the gram-scale transformations and product derivatization (Scheme 3). The cycloaddition of 1a with 2a on the 4 mmol scale proceeded well to afford tetrahydrofuran 3aa in 80% yield (0.94 g) with 93% ee and a 12:1 diastereomeric ratio. Reduction of nitro- group of 3aa and subsequent acylation with 4-bromobenzoyl chloride furnished compound 5 in 83% yield for the two steps. The absolute configuration of 5 was unambiguously assigned by X-ray crystallography (CCDC1863525). Next we tried to elaborate the tetrahydrofuran 3aa into bicyclic heterocycles 7. The tetrahydrofuran 3aa underwent reduction, tosylation and subsequent allylation to afford compound 6 in 55% of total yield. Ring-closing metathesis of 6 with Grubbs first generation catalyst gave octahydrofuro[3,4-b]pyridine 7 in 97% yield. In conclusion, we have developed an efficient method for the enantio- and diastereoselective construction of multisubstituted tetrahydrofurans via asymmetric decarboxylative cycloaddition of VECs with β-nitroolefins under cooperative catalysis system of palladium complex and squaramide. By using a palladium complex generated in situ from Pd2(dba)3•CHCl3 and phosphoramidite L1 and chiral squaramide OC4 as cooperative catalysts under mild conditions, the cycloaddition reaction provided multisubstituted tetrahydrofurans bearing a quaternary stereocenter in good to high yields with acceptably high enantio- and diastereoselectivities. The synthetic utility of the process has been demonstrated by the gram-scale transformation and the product derivatization. Further studies to expand the scope of the cycloaddition reaction through zwitterionic allylpalladium intermediates are currently underway and will be reported in due course.
ASSOCIATED CONTENT
REFERENCES (1)
(3)
(4)
(5)
Supporting Information. Detailed experimental procedures; characterization data of all of the new compounds; copies of HPLC chromatographies, 1H and 13C NMR spectra of the products. This material is available free of charge via the Internet at http://pubs.acs.org.
Corresponding Author
This work was supported by the National Natural Science Foundation of China (21572130, 21871179). We thank Mr. Hong Jiang and Prof. Yong Cui for X-ray crystallography analysis. We thank the Instrumental Analysis Center of Shanghai Jiao Tong University for HRMS analysis.
(2)
5 CCDC1863525
AUTHOR INFORMATION
The authors declare no competing financial interests.
ACKNOWLEDGMENT
Ph 5
1) Zn, 1 N HCl 2) TsCl 3) allylic bromide Ts N
Ph
2) 4-bromobenzoyl chloride 83%
*
[email protected] Notes
O
1) Zn, 1 N HCl
O
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Trost, B. M.; Chan, D. M. T. New Conjunctive Reagents. 2Acetoxymethyl-3-allyltrimethylsilane for Methylenecyclopentane Annulations Catalyzed by Palladium(0). J. Am. Chem. Soc. 1979, 101, 6429-6432. For selected reviews, see: (a) Souillart, L.; Cramer, N. Catalytic C−C Bond Activations via Oxidative Addition to Transition Metals. Chem. Rev. 2015, 115, 9410-9464. (b) Weaver, J. D.; A. Recio, A., III; Grenning, A. J.; Tunge, J. A. Transition Metal-Catalyzed Decarboxylative Allylation and Benzylation Reactions. Chem. Rev. 2011, 111, 1846-1913. (c) Chan, D. M. T. in Cycloaddition Reactions in Organic Synthesis; Kobayashi, S.; Jørgensen, K. A., Eds.; WILEYVCH, Weinheim, 2002, p 57. For selected reviews, see: (a) He, J.; Ling, J.; Chiu, P. Vinyl Epoxides in Organic Synthesis. Chem. Rev. 2014, 114, 80378128. (b) Pineschi, M.; Bertolini, F.; Di Bussolo, V.; Crotti, P. Regio- and Stereoselective Ring Opening of Allylic Epoxides. Curr. Org. Synth. 2009, 6, 290-324. For selected examples, see: (a) Gao, R.-D.; Xu, Q.-L.; Dai, L.X.; You, S.-L. Pd-Catalyzed Cascade Allylic Alkylation and Eearomatization Reactions of Indoles with Vinyloxirane. Org. Biomol. Chem. 2016, 14, 8044-8046. (b) Liu, H.; Liu, G.; Qiu, G.; Pu, S.; Wu, J. A silver(I)-rhodium(I) cooperative catalysis in the reaction of N'-(2alkynylbenzylidene)hydrazide with 2-vinyloxirane. Tetrahedron 2013, 69, 1476-1480. (c) Feng, J.-J.; Zhang, J. An Atom-Economic Synthesis of Bicyclo[3.1.0]hexanes by Rhodium N-Heterocyclic Carbene-Catalyzed Diastereoselective Tandem Hetero-[5 + 2] Cycloaddition/Claisen Rearrangement Reaction of Vinylic Oxiranes with Alkynes. J. Am. Chem. Soc. 2011, 133, 73047307. (d) Shim, J. G.; Yamamoto, Y. A Novel and Effective Route to 1,3-Oxazolidine Derivatives. Palladium-Catalyzed Regioselective [3 + 2] Cycloaddition of Vinylic Oxiranes with Imines. Tetrahedron Lett. 1999, 40, 1053-1056. (e) Shim, J. G.; Yamamoto, Y. Palladium-Catalyzed Regioselective [3 + 2] Cycloaddition of Vinylic Oxiranes with Activated Olefins. A Facile Synthesis of Tetrahydrofuran Derivatives. J. Org. Chem. 1998, 63, 30673071. (f) Trost, B. M.; Sudhakar, A. R. A Stereoselective Contrasteric Conversion of Epoxides to cis-Oxazolidin-2ones. J. Am. Chem. Soc. 1988, 110, 7933-7935. (g) Trost, B. M.; Angle, S. R. Palladium-Mediated Vicinal Cleavage of Allyl Epoxides with Retention of Stereochemistry: A Cis Hydroxylation Equivalent. J. Am. Chem. Soc. 1985, 107, 6123-6124. For asymmetric cycloaddition of vinyl epoxides with unsaturated electrophiles, see: (a) Cheng, Q.; Zhang, F.; Cai, Y.; Guo, Y.-L.; You, S.-L. Stereodivergent Synthesis of Tetrahydrofuroindoles through Pd-Catalyzed Asymmetric Dearomative Formal [3 + 2] Cycloaddition. Angew. Chem., Int. Ed. 2018, 57, 2134-2138. (b) Cheng, Q.; Zhang, H. J.; Yue, W. J.; You, S. L. Palladium-Catalyzed Highly Stereoselective Dearomative [3 + 2] Cycloaddition of Nitrobenzofurans. Chem. 2017, 3, 428-436. (c) Suo, J.-J.; Du, J.; Liu, Q.-R.; Chen, D.; Ding, C.-H.; Peng, Q.; Hou, X.-L. Highly Diastereo- and Enantioselective Palladium-Catalyzed
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[3 + 2] Cycloaddition of Vinyl Epoxides and α,β-Unsaturated Ketones. Org. Lett. 2017, 19, 6658-6661. (d) Ma, C.; Huang, Y.; Zhao, Y. Stereoselective 1,6-Conjugate Addition/Annulation of para-Quinone Methides with Vinyl Epoxides/Cyclopropanes. ACS Catal. 2016, 6, 6408-6412. (e) Wu, W.-Q.; Ding, C.-H.; Hou, X.-L. Pd-Catalyzed Diastereo- and Enantioselective [3 + 2]-Cycloaddition Reaction of Vinyl Epoxide with Nitroalkenes. Synlett 2012, 23, 1035-1038. (f) Liu, Z.; Feng, X.; Du, H. RhodiumCatalyzed Asymmetric Formal Cycloadditions of Racemic Butadiene Monoxide with Imines. Org. Lett. 2012, 14, 31543157. (g) Shaghafi, M. B.; Grote, R. E.; Jarvo, E. R. Oxazolidine Synthesis by Complementary Stereospecific and Stereoconvergent Methods. Org. Lett. 2011, 13, 5188-5191. (h) Raghunath, M.; Zhang, X. A Correlation Study of Bisphosphine Ligand Bite Angles with Enantioselectivity in Pd-Catalyzed Asymmetric Transformations. Tetrahedron Lett. 2005, 46, 8213-8216. (i) Trost, B. M.; McEachern, E. J. Inorganic Carbonates as Nucleophiles for the Asymmetric Synthesis of Vinylglycidols. J. Am. Chem. Soc. 1999, 121, 8649-8650. (j) Larksarp, C.; Alper, H. Palladium(0)Catalyzed Asymmetric Cycloaddition of Vinyloxiranes with Heterocumulenes Using Chiral Phosphine Ligands: An Effective Route to Highly Enantioselective Vinyloxazolidine Derivatives. J. Am. Chem. Soc. 1997, 119, 3709-3715. (a) Khan, I.; Zhao, C.; Zhang, Y. J. Pd-Catalyzed Asymmetric Decarboxylative Cycloaddition of Vinylethylene Carbonates with 3-Cyanochromones. Chem. Commun. 2018, 54, 4708-4711. (b) Khan, A.; Khan, S.; Khan, I.; Zhao, C.; Mao, Y.; Chen, Y.; Zhang, Y. J. Enantioselective Construction of Tertiary C–O Bond via Allylic Substitution of Vinylethylene Carbonates with Water and Alcohols. J. Am. Chem. Soc. 2017, 139, 10733-10741. (c) Yang, L.; Khan, A.; Zheng, R.; Jin, L. Y.; Zhang, Y. J. Pd-Catalyzed Asymmetric Decarboxylative Cycloaddition of Vinylethylene Carbonates with Imines. Org. Lett. 2015, 17, 6230-6233. (d) Khan, A.; Zhang, Y. J. Palladium-Catalyzed Asymmetric Decarboxylative Cycloaddition of Vinylethylene Carbonates with Electrophiles: Construction of Quaternary Stereocenters. Synlett 2015, 26, 853-860. (e) Khan, A.; Xing, J.; Zhao, J.; Kan, Y.; Zhang, W.; Zhang, Y. J. Palladium-Catalyzed Enantioselective Decarboxylative Cycloaddition of Vinylethylene Carbonates with Isocyanates. Chem. - Eur. J. 2015, 21, 120-124. (f) Khan, A.; Zheng, R.; Kan, Y.; Ye, J.; Xing, J.; Zhang, Y. J. Palladium-Catalyzed Decarboxylative Cycloaddition of Vinylethylene Carbonates with Formaldehyde: Enantioselective Construction of Tertiary Vinylglycols. Angew. Chem., Int. Ed. 2014, 53, 6439-6442. (g) Khan, A.; Yang, L.; Xu, J.; Jin, L. Y.; Zhang, Y. J. Palladium-Catalyzed Asymmetric Decarboxylative Cycloaddition of Vinylethylene Carbonates with Michael Acceptors: Construction of Vicinal Quaternary Stereocenters. Angew. Chem., Int. Ed. 2014, 53, 11257-11260. (a) Yang, L.-C.; Tan, Z. Y.; Rong, Z.-Q.; Liu, R.; Wang, Y.N.; Zhao, Y. Palladium-Titanium Relay Catalysis Enables Switch from Alkoxide-π-Allyl to Dienolate Reactivity for Spiro-Heterocycle Synthesis. Angew. Chem., Int. Ed. 2018, 57, 7860-7864. (b) Yang, L.-C.; Rong, Z.-Q.; Wang, Y.-N.; Tan, Z. Y.; Wang, M.; Zhao, Y. Construction of NineMembered Heterocycles through Palladium-Catalyzed Formal [5 + 4] Cycloaddition. Angew. Chem., Int. Ed. 2017, 56, 2927-2931. (c) Rong, Z.-Q.; Yang, L.-C.; Liu, S.; Yu, Z.; Wang, Y.-N.; Tan, Z. Y.; Huang, R.-Z.; Lan, Y.; Zhao, Y. Nine-Membered Benzofuran-Fused Heterocycles: Enantioselective Synthesis by Pd-Catalysis and Rearrangement via Transannular Bond Formation. J. Am. Chem. Soc. 2017, 139, 15304-15307. (d) Singha, S.; Patra, T.; Daniliuc, C. G.; Glorius, F. Highly Enantioselective [5 + 2] Annulations through Cooperative N-Heterocyclic Carbene (NHC) Organocatalysis and Palladium Catalysis. J. Am. Chem. Soc. 2018, 140, 3551-3554. (e) Yuan, C.; Wu, Y.;
Wang, D.; Zhang, Z.; Wang, C.; Zhou, L.; Zhang, C.; Song, B.; Guo, H. Formal [5 + 3] Cycloaddition of Zwitterionic Allylpalladium Intermediates with Azomethine Imines for Construction of N,O-Containing Eight-Membered Heterocycles. Adv. Synth. Catal. 2018, 360, 652-658. (f) Das, P.; Gondo, S.; Nagender, P.; Uno, H.; Tokunaga, E.; Shibata, N. Access to Benzo-fused Nine-membered Heterocyclic Alkenes with a Trifluoromethyl Carbinol Moiety via a Double Decarboxylative Formal Ring-expansion Process under Palladium Catalysis. Chem. Sci. 2018, 9, 3276-3281. (g) Zhao, H.-W.; Du, J.; Guo, J.-M.; Feng, N.-N.; Wang, L.R.; Ding, W.-Q.; Song, X.-Q. Formal [5 + 2] Cycloaddition of Vinylethylene Carbonates to Oxazol-5-(4H)-ones for the Synthesis of 3,4-Dihydrooxepin-2(7H)-ones. Chem. Commun. 2018, 54, 9178-9181. (8) During the studies on the decarboxylative cycloaddition of VECs with unsaturated electrophiles, we found that α,βunsaturated aldehydes 4 were formed when the eletrophilicity of the electrophiles is not strong enough. Also see: (a) Guo, W.; Kuniyil, R.; Gómez, J. E.; Maseras, F.; Kleij, A. W. A Domino Process toward Functionally Dense Quaternary Carbons through Pd-Catalyzed Decarboxylative C(sp3)–C(sp3) Bond Formation. J. Am. Chem. Soc. 2018, 140, 3981-3987. (b) Shimizu, I.; Sugiura, T.; Tsuji, J. Facile Synthesis of β-Aryl- or β-Alkenyl-β-methyl-α,β-unsaturated Carbonyl Compounds by Palladium-Catalyzed Reaction of l,2-Dien-4-ols with Aryl or Alkenyl Halides. J. Org. Chem. 1985, 50, 537-539. (9) For selected reviews, see: (a) Maji, B. N-HeterocyclicCarbene-Catalyzed Reactions of Nitroalkenes: Synthesizing Important Building Blocks. Asian J. Org. Chem. 2018, 7, 7084. (b) Sukhorukov, A. Y.; Sukhanova, A. A.; Zlotin, S. G. Stereoselective Reactions of Nitro Compounds in the Synthesis of Natural Compound Analogs and Active Pharmaceutical Ingredients. Tetrahedron 2016, 72, 61916281. (c) Yan, W.; Shi, X.; Zhong, C. Secondary Amines as Lewis Bases in Nitroalkene Activation. Asian J. Org. Chem. 2013, 2, 904-914. (d) Somanathan, R.; Chávez, D.; Servín, F. A.; Romero, J. A.; Navarrete, A.; Parra-Hake, M.; Aguirre, G.; de Parrodi, C. A.; González, J. Bifunctional Organocatalysts in the Asymmetric Michael Additions of Carbonylic Compounds to Nitroalkenes. Curr. Org. Chem. 2012, 16, 2440-2461. (e) Berner, O. M.; Tedeschi, L.; Enders, D. Asymmetric Michael Additions to Nitroalkenes. Eur. J. Org. Chem. 2002, 1877-1894. (10) For selected reviews, see: (a) Zhao, B.-L.; Li, J. H.; Du, D.M. Squaramide-Catalyzed Asymmetric Reactions. Chem. Rec. 2017, 17, 994-1018. (b) Rouf, A.; Tanyeli, C. Squaramide Based Organocatalysts in Organic Transformations. Curr. Org. Chem. 2016, 20, 2996-3013. (c) Alemán, J.; Parra, A.; Jiang, H.; Jørgensen, K. A. Squaramides: Bridging from Molecular Recognition to Bifunctional Organocatalysis. Chem. - Eur. J. 2011, 17, 6890-6899. (11) For selected reviews, see: (a) Fu, J.; Huo, X.; Li, B.; Zhang, W. Cooperative Bimetallic Catalysis in Asymmetric Allylic Substitution. Org. Biomol. Chem. 2017, 15, 9747-9759. (b) Afewerki, S.; Córdova, A. Combinations of Aminocatalysts and Metal Catalysts: A Powerful Cooperative Approach in Selective Organic Synthesis. Chem. Rev. 2016, 116, 1351213570. (c) Sun, Z.; He, J.; Qu, M.; Li, K. Progress of Cooperative Catalysis in Organic Synthesis. Chin. J. Org. Chem. 2015, 35, 1250-1259. (d) Inamdar, S. M.; Shinde, V. S.; Patil, N. T. Enantioselective Cooperative Catalysis. Org. Biomol. Chem. 2015, 13, 8116-8162. (e) Chen, D.-F.; Han, Z.Y.; Zhou, X.-L.; Gong, L.-Z. Asymmetric Organocatalysis Combined with Metal Catalysis: Concept, Proof of Concept, and Beyond. Acc. Chem. Res. 2014, 47, 2365-2377. (f) Du, Z. T.; Shao, Z. H. Combining Transition Metal Catalysis and Organocatalysis – An Update. Chem. Soc. Rev. 2013, 42, 1337-1378. (g) Lv, F.; Liu, S.; Hu, W. Recent Advances in
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the Use of Chiral Brønsted Acids as Cooperative Catalysts in Cascade and Multicomponent Reactions. Asian J. Org. Chem. 2013, 2, 824-836. (h) Park, J.; Hong, S. Cooperative Bimetallic Catalysis in Asymmetric Transformations. Chem. Soc. Rev. 2012, 41, 6931-6943. (i) Allen, A. E.; MacMillan, D. W. C. Synergistic Catalysis: A Powerful Synthetic Strategy for New Reaction Development. Chem. Sci. 2012, 3, 633-658. Chen, G.; Deng, Y.; Gong, L.; Mi, A.; Cui, X.; Jiang, Y.; Choi, M. C. K.; Chan, A. S. C. Palladium-catalyzed Allylic Alkylation of tert-Butyl(diphenylmethylene)-glycinate with Simple Allyl Esters under Chiral Phase Transfer Conditions. Tetrahedron: Asymmetry 2001, 12, 1567-1571. Nakoji, M.; Kanayama, T.; Okino, T.; Takemoto, Y. Chiral Phosphine-Free Pd-Mediated Asymmetric Allylation of Prochiral Enolate with a Chiral Phase-Transfer Catalyst. Org. Lett. 2001, 3, 3329-3331. Only one report for the asymmetric allylic alkylation under cooperative catalysis system of palladium complex and thiourea, see: Boucherif, A.; Duan, S.-W.; Yuan, Z.-G.; Lu, L.-Q.; Xiao, W.-J. Catalytic Asymmetric Allylation of 3Aryloxindoles by Merging Palladium Catalysis and Asymmetric H-Bonding Catalysis. Adv. Synth. Catal. 2016, 358, 2594-2598. Feringa, B. L.; Pineschi, M.; Arnold, L. A.; Imbos, R.; de Vries, A. H. M. Highly Enantioselective Catalytic Conjugate Addition and Tandem Conjugate Addition–Aldol Reactions of Organozinc Reagents. Angew. Chem., Int. Ed. 1997, 36, 2620-2623. Zhou, H.; Wang, W.-H.; Fu, Y.; Xie, J.-H.; Shi, W.-J.; Wang, L.-X.; Zhou, Q.-L. Highly Enantioselective CopperCatalyzed Conjugate Addition of Diethylzinc to Enones Using Chiral Spiro Phosphoramidites as Ligands. J. Org. Chem. 2003, 68, 1582-1584. (a) Zhu, Y.; Malerich, J. P.; Rawal, V. H. SquaramideCatalyzed Enantioselective Michael Addition of Diphenyl Phosphite to Nitroalkenes. Angew. Chem., Int. Ed. 2010, 49, 153-156. (b) Konishi, H.; Lam, T. Y.; Malerich, J. P.; Rawal, V. H. Enantioselective α-Amination of 1,3-Dicarbonyl Compounds Using Squaramide Derivatives as Hydrogen Bonding Catalysts. Org. Lett. 2010, 12, 2028-2031.
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ACS Catalysis
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