叔胺催化Aza-Michael加成反应的研究
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摘要
自21世纪初Barbas,List,Jacobsen,J?rgensen, MacMillan等开拓性的研究工作之后,有机催化领域正吸引着越来越多研究者的关注和加入,“有机催化的金色时代”已经悄悄来临。2000年至今,有机催化发展异常迅速,几乎每天都有新的有机催化反应例子的报道出现在电子期刊中。但不对称有机催化的aza-Michael加成反应直到2005年底才有一篇相关的报道,机遇和挑战都激起了我们开展本文工作的兴趣。
本论文为建立一个手性叔胺类有机小分子催化的不对称aza-Michael加成反应体系进行了初步的尝试。
首先基于已报道过的氮亲核子,我们设计并合成了肼的衍生物、磺酰胺和酰亚胺三大类不同的氮亲核子;并在奎宁催化的对β-硝基苯乙烯共轭加成的模型反应中进行评价,成功地筛选出了活性最高的氮亲核子——4-硝基邻苯二甲酰亚胺。
随后对4-硝基邻苯二甲酰亚胺与硝基烯烃的有机催化不对称Michael加成进行了较为系统的研究。对催化剂、溶剂、反应温度、反应时间等影响因素分别进行了考察。在优化后的反应条件下,获得了最高93%的产率和11%的对映选择性。
最后对4-硝基邻苯二甲酰亚胺的Michael受体的普适性也进行了考察,考察了4-硝基邻苯二甲酰亚胺对α,β-不饱和醛、α,β-不饱和酮、α,β-不饱和羧酸酯以及α,β-不饱和酰胺等Michael受体的共轭加成活性,并与邻苯二甲酰亚胺做了平行的比较。
Since the ground-breaking work of Barbas, List, Jacobsen, J?rgensen, MacMillan and many other researchers in the early 2000s, the field of organocatalysis has attracted more and more attention and participation.“The golden age of organocatalysis”has already dawned. Under the breathtaking pace of growth in the field of organocatalysis since 2000, a day hardly passes without a new organocatalytic reaction emerging in the electronic journals. However, only one article with regard to asymmetric organocatalytic intermolecular aza-Michael addition had been reported by the end of 2005, both opportunities and challenges triggered us to carry out the work in this thesis.
To develope a reaction system of asymmetric organocatalytic aza-Michael addition catalyzed by tertiary amines, some preliminary investigation was conducted. Firstly, three types of N-nucleophiles including hydrazine derivatives, sulfonamides and imides were designed and prepared. After the evaluation in the model reaction of conjugate addition ofβ-nirtostyrene catalyzed by quinine, 4-nitrophthalimide was screened out as the most efficient N-nucleophile.
The organocatalytic aza-Michael addition of 4-nitrophthalimide to nitroolefins was systematically studied in the second part of this work, and the effects of catalyst, solvent, temperature and reaction time were evaluated successively. A high yield up to 93% and a moderate enatioselectivity of 11% e.e. were gained under the optimized reaction conditions.
Finally, we examined the scope of Michael acceptors of 4-nitrophthalimide. The activities of conjugate addition of 4-nitrophthalimide to a series of Michael acceptor such asα,β-unsaturated aldehydes, ketones, carboxylic esters and amides were investigated. A parallel experiment using phthalimide as the N-nucleophile was also conducted.
本论文为建立一个手性叔胺类有机小分子催化的不对称aza-Michael加成反应体系进行了初步的尝试。
首先基于已报道过的氮亲核子,我们设计并合成了肼的衍生物、磺酰胺和酰亚胺三大类不同的氮亲核子;并在奎宁催化的对β-硝基苯乙烯共轭加成的模型反应中进行评价,成功地筛选出了活性最高的氮亲核子——4-硝基邻苯二甲酰亚胺。
随后对4-硝基邻苯二甲酰亚胺与硝基烯烃的有机催化不对称Michael加成进行了较为系统的研究。对催化剂、溶剂、反应温度、反应时间等影响因素分别进行了考察。在优化后的反应条件下,获得了最高93%的产率和11%的对映选择性。
最后对4-硝基邻苯二甲酰亚胺的Michael受体的普适性也进行了考察,考察了4-硝基邻苯二甲酰亚胺对α,β-不饱和醛、α,β-不饱和酮、α,β-不饱和羧酸酯以及α,β-不饱和酰胺等Michael受体的共轭加成活性,并与邻苯二甲酰亚胺做了平行的比较。
Since the ground-breaking work of Barbas, List, Jacobsen, J?rgensen, MacMillan and many other researchers in the early 2000s, the field of organocatalysis has attracted more and more attention and participation.“The golden age of organocatalysis”has already dawned. Under the breathtaking pace of growth in the field of organocatalysis since 2000, a day hardly passes without a new organocatalytic reaction emerging in the electronic journals. However, only one article with regard to asymmetric organocatalytic intermolecular aza-Michael addition had been reported by the end of 2005, both opportunities and challenges triggered us to carry out the work in this thesis.
To develope a reaction system of asymmetric organocatalytic aza-Michael addition catalyzed by tertiary amines, some preliminary investigation was conducted. Firstly, three types of N-nucleophiles including hydrazine derivatives, sulfonamides and imides were designed and prepared. After the evaluation in the model reaction of conjugate addition ofβ-nirtostyrene catalyzed by quinine, 4-nitrophthalimide was screened out as the most efficient N-nucleophile.
The organocatalytic aza-Michael addition of 4-nitrophthalimide to nitroolefins was systematically studied in the second part of this work, and the effects of catalyst, solvent, temperature and reaction time were evaluated successively. A high yield up to 93% and a moderate enatioselectivity of 11% e.e. were gained under the optimized reaction conditions.
Finally, we examined the scope of Michael acceptors of 4-nitrophthalimide. The activities of conjugate addition of 4-nitrophthalimide to a series of Michael acceptor such asα,β-unsaturated aldehydes, ketones, carboxylic esters and amides were investigated. A parallel experiment using phthalimide as the N-nucleophile was also conducted.
引文
[1] Dalko P. I., Moisan L. In the Golden Age of Organocatalysis. Angew. Chem. Int. Ed., 2004, 43(39): 5138-5175.
[2] Berkessel A., Gr?ger H. Asymmetric Organocatalysis. Weinheim: Wiley-VCH, 2004: 1-433.
[3] Akiyama T., Itoh J., Yokota K. et al. Enantioselective Mannich-Type Reaction Catalyzed by a Chiral Br?nsted Acid. Angew. Chem. Int. Ed., 2004, 43(12): 1566-1569.
[4] Akiyama T., Itoh J., Fuchibe K. Recent Progress in Chiral Br?nsted Acid Catalysis. Adv. Synth. Catal., 2006, 348(9): 999-1010.
[5] Taylor M. S., Jacobsen E. N. Asymmetric Catalysis by Chiral Hydrogen-bond Donors. Angew. Chem. Int. Ed., 2006, 45(10): 1520-1543.
[6] Alma?i D., Alonso D. A., Nájera C. Organocatalytic Asymmetric Conjugate Additions. Tetrahedron: Asymmetry, 2007, 18(3): 299-365.
[7] Tsogoeva S. B. Recent Advances in Asymmetric Organocatalytic 1,4-Conjugate Additions. Eur. J. Org. Chem., 2007, 2007(11): 1701-1716.
[8] Xu L. W., Xia C. G. A Catalytic Enantioselective Aza-Michael Reaction: Novel Protocols for Asymmetric Synthesis ofβ-Amino Carbonyl Compounds. Eur. J. Org. Chem., 2005, 2005(4): 633-639.
[9] Myers J. K., Jacobsen E. N. Asymmetric Synthesis ofα-Amino Acid Derivatives via Catalytic Conjugate Addition of Hydrazoic Acid to Unsaturated Imides. J. Am. Chem. Soc., 1999, 121(38): 8959-8960.
[10] Horstmann T. E., Guerin D. J., Miller S. J. Asymmetric Conjugate Addition of Azide toα,β-Unsaturated Carbonyl Compounds Catalyzed by Simple Peptides. Angew. Chem. Int. Ed., 2000, 39(20): 3635-3638.
[11] Horstmann T. E., Guerin D. J., Miller S. J. Amine-Catalyzed Addition of AzideIon toα,β-Unsaturated Carbonyl Compounds. Org. Lett., 1999, 1(7): 1107-1109.
[12] Guerin D. J., Miller S. J. Asymmetric Azidation-Cycloaddition with Open-Chain Peptide-Based Catalysts: A Sequential Enantioselective Route to Triazoles. J. Am. Chem. Soc., 2002, 124(10): 2134-2136.
[13] Wang J., Li H., Wang W. et al. Enantioselective Organocatalytic Michael Addition Reactions between N-Heterocycles and Nitroolefins. Org. Lett., 2006, 8(7): 1391-1394.
[14] Chen Y. K.; Yoshida, M.; MacMillan, D. W. C. Enantioselective Organocatalytic Amine Conjugate Addition. J. Am. Chem. Soc., 2006, 128(29): 9328-9329.
[15] Perdicchia D. and J?rgensen K. A. Asymmetric Aza-Michael Reactions Catalyzed by Cinchona Alkaloids. J. Org. Chem., 2007, 72(9): 3565-3568.
[16] Hiemstra H., Wynberg H. Addition of Aromatic Thiols to Conjugated Cycloalkenones, Catalyzed by Chiralβ-Hydroxy Amines. J. Am. Chem. Soc., 1981, 103(2): 417-430.
[17] Dinor P., Nielsen M., J?rgensen K. A. et al. Enantioselective Organocatalytic Conjugate Addition of N-Heterocycles toα,β-Unsaturated Aldehydes. Angew. Chem. Int. Ed., 2007, 46(12): 1983-1987.
[18] Ibrahem I., Rios R., Córdova A. et al. Organocatalytic Asymmetric 5-Hydroxyisoxazolidine Synthesis: A Highly Enantioselective Route toβ-Amino Acids. Chem. Commun., 2007, 2007(8): 849-851.
[19] Kiyosei T., Soumen M., Masataka I. Asymmetric Intramolecular Aza-Michael Reaction Using Environmentally Friendly Organocatalysis. Heterocycles, 2003, 59(1): 51-55.
[20] Yamamoto Y., Momiyama N., Yamamoto H. Enantioselective Tandem O-Nitroso Aldol/Michael Reaction. J. Am. Chem. Soc., 2004, 126(19): 5962-5963.
[21] Hayashi Y., Yamaguchi J., Koshino H. A Highly Active 4-Siloxyproline Catalyst for Asymmetric Synthesis. Adv. Synth. Catal., 2004, 346(12): 1435-1439.
[22] Itoh T., Yokoya, M., Miyauchi K. Total Synthesis of Ent-Dihydrocorynantheol by Using a Proline-Catalyzed Asymmetric Addition Reaction. Org. Lett., 2006, 8(8): 1533-1535.
[23] Bertelsen S., Diner P., J?rgensen K. A. Asymmetric Organocatalyticβ-Hydroxylation ofα,β-Unsaturated Aldehydes. J. Am. Chem. Soc., 2007, 129(6): 1536-1537.
[24] Xun S. D., Gaetan L., Zhang J. D. et al. Tuning the Electrical and Optical Properties of Dinuclear Ruthenium Complexes for Near Infrared Optical Sensing. Org. Lett., 2006, 8(8): 1697-1700.
[25] Saul G. C., Robert Z., Colin S. Preparation and Kinetics of Decomposition of a Bicyclic Aza Compound. A Novel Reduction. J. Am. Chem. Soc., 1961, 83(10): 2895-2900.
[26] Jacbos R. L. Oxidation of p-Toluenesulfonylhydrazide to 1,2-Di (p-toluenesulfonyl)hydrazine. J. Org. Chem., 1977, 42(3): 571-573.
[27] Lis R. and Marisca A. J. Methanesulfonanilides and the Mannich Reaction. J. Org. Chem., 1987, 52(19): 4377-4379.
[28] Sundberg R. J. and Laurino J. P. Cyclization of 2-[N-(Methylsulfonyl)anilino] -acetaldehyde Diethyl Acetals to Indoles. Evidence for Stereoelectronic Effects in Intramolecular Electrophilic Aromatic Substitution. J. Org. Chem., 1984, 49(2): 249-254.
[29] Teichert A., Jantos K., Studer A. et al. One-Pot Homolytic Aromatic Substitutions/HWE Olefinations under Microwave Conditions for the Formation of a Small Oxindole Library. Org. Lett., 2004, 6(20): 3477-3480.
[30] Jose B., Francisco J. F., Jose M. I. et al. 2-Arylallyl as a New Protecting Group for Amines, Amides and Alcohols. Chem. Commun., 2005, 2005(7): 933-935.
[31] Lei M., Tao, X. L. Wang Y. G. A Practical, Water-Soluble, Ionic Scavenger for the Solution-phase Syntheses of Amides. Helvetica Chimica Acta, 2006, 89(3):532-536.
[32] Koh K., Lee J. B., Ryu J. Photo-Fries Rearrangement of N-Arylsulfonamides to Aminoaryl Sulfone Derivatives. Tetrahedron, 2003, 59(39): 7651-7659.
[33] Ahmad R. M., Foad K., Ahmad R. M. et al. A Mild and Chemoselective Solvent-Free Method for the Synthesis of N-Aryl and N-Alkylsulfonamides. Letters in Organic Chemistry, 2006, 3(3): 235-241.
[34] Mansfeld M., Parik M. and Ludwig M. Effect of Para-Substitution on Dissociation of N-Phenylbenzenesulfonamides. Collect. Czech. Chem. Commun., 2004, 69(7): 1479-1490.
[35] Lyapkalo I. M., Reissig H. U., Schofer A. et al. Study of Unusually High Rotational Barriers about S-N Bonds in Nonafluorobutane-1-sulfonamides: The Electronic Nature of the Torsional Effect. Helvetica Chimica Acta, 2002, 85(12): 4206-4215.
[36] Lee B. K., Kim M. S., Leea W. K. et al. An Efficient Synthesis of Chiral Terminal 1,2-Diamines Using an Enantiomerically Pure [1-(10R)-Methylbenzyl] aziridine-2-yl]methanol. Tetrahedron, 2006, 62(35): 8393-8397.
[37] O’Neil I. A., Cleator E., Southern J. M. et al. The Stereospecific Addition of Hydroxylamines toα,β-Unsaturated Sulfones, Nitriles and Nitro Compounds. Tetrahedron Letters, 2001, 42(46): 8251-8254.
[38] Sabelle S., Lucet D., Mioskowski C. et al. Enantioselective Synthesis ofα-Amino Acids from Nitroalkenes. Tetrahedron Letters, 1998, 39(15): 2111-2114.
[39] Bowman R. K. and Johnson J. S. Lewis Acid Catalyzed Dipolar Cycloadditions of Imidates. J. Org. Chem., 2004, 69(24): 8537-8540.
[40] Liu J. T and Yao C. F. One-Pot Synthesis of Trans-β-Alkylstyrenes. Tetrahedron Letters, 2001, 42(35): 6147-6150.
[41] France S., Wack H., Taggi A. E. et al. Catalytic Asymmetricα-Chlorination of Acid Halides. J. Am. Chem. Soc., 2004, 126(13): 4245-4255.
[42] Li H. M., Wang Y., Deng L. et al. Highly Enantioselective Conjugate Addition of Malonate and Ketoester to Nitroalkenes: Asymmetric C-C Bond Formation with New Bifunctional Organic Catalysts Based on Cinchona Alkaloids. J. Am. Chem. Soc., 2004, 126(32): 9906-9907.
[43] Bikash P., Prasun K. P., Parasuraman J. et al. First Triphenylphosphine-Promoted Reduction of Maleimides to Succinimides. Synthesis, 2003, 2003(10): 1549-1552.
[44] Kishan P. H., Santosh B. M., Narshinha P. A. Cyanuric Chloride: Decent Dehydrating Agent for an Exclusive and Efficient Synthesis of Kinetically Controlled Isomaleimides. Tetrahedron, 2006, 62(5): 937-942.
[45] Antoioletti R., Bovicelli P., Malancona S. A New Route to 2-Alkenyl-1,3-dicarbonyl Compounds Intermediates in the Synthesis of Dihydrofurans. Tetrahedron, 2002, 58(3): 589-596.
[46] Lucet D.; Sabelle S.; Kostelitz O. et al. Enantioselective Synthesis ofα-Amino Acids and Monosubstituted 1,2-Diamines by Conjugate Addition of 4-Phenyl-2-oxazolidinone to Nitro Alkenes. Eur. J. Org. Chem., 1999, 1999(10): 2583-2591.
[47] Liu M. and Sibi M. P. Recent Advances in the Stereoselective Synthesis ofβ-Amino Acids. Tetrahedron, 2002, 58(40): 7991-8035.
[2] Berkessel A., Gr?ger H. Asymmetric Organocatalysis. Weinheim: Wiley-VCH, 2004: 1-433.
[3] Akiyama T., Itoh J., Yokota K. et al. Enantioselective Mannich-Type Reaction Catalyzed by a Chiral Br?nsted Acid. Angew. Chem. Int. Ed., 2004, 43(12): 1566-1569.
[4] Akiyama T., Itoh J., Fuchibe K. Recent Progress in Chiral Br?nsted Acid Catalysis. Adv. Synth. Catal., 2006, 348(9): 999-1010.
[5] Taylor M. S., Jacobsen E. N. Asymmetric Catalysis by Chiral Hydrogen-bond Donors. Angew. Chem. Int. Ed., 2006, 45(10): 1520-1543.
[6] Alma?i D., Alonso D. A., Nájera C. Organocatalytic Asymmetric Conjugate Additions. Tetrahedron: Asymmetry, 2007, 18(3): 299-365.
[7] Tsogoeva S. B. Recent Advances in Asymmetric Organocatalytic 1,4-Conjugate Additions. Eur. J. Org. Chem., 2007, 2007(11): 1701-1716.
[8] Xu L. W., Xia C. G. A Catalytic Enantioselective Aza-Michael Reaction: Novel Protocols for Asymmetric Synthesis ofβ-Amino Carbonyl Compounds. Eur. J. Org. Chem., 2005, 2005(4): 633-639.
[9] Myers J. K., Jacobsen E. N. Asymmetric Synthesis ofα-Amino Acid Derivatives via Catalytic Conjugate Addition of Hydrazoic Acid to Unsaturated Imides. J. Am. Chem. Soc., 1999, 121(38): 8959-8960.
[10] Horstmann T. E., Guerin D. J., Miller S. J. Asymmetric Conjugate Addition of Azide toα,β-Unsaturated Carbonyl Compounds Catalyzed by Simple Peptides. Angew. Chem. Int. Ed., 2000, 39(20): 3635-3638.
[11] Horstmann T. E., Guerin D. J., Miller S. J. Amine-Catalyzed Addition of AzideIon toα,β-Unsaturated Carbonyl Compounds. Org. Lett., 1999, 1(7): 1107-1109.
[12] Guerin D. J., Miller S. J. Asymmetric Azidation-Cycloaddition with Open-Chain Peptide-Based Catalysts: A Sequential Enantioselective Route to Triazoles. J. Am. Chem. Soc., 2002, 124(10): 2134-2136.
[13] Wang J., Li H., Wang W. et al. Enantioselective Organocatalytic Michael Addition Reactions between N-Heterocycles and Nitroolefins. Org. Lett., 2006, 8(7): 1391-1394.
[14] Chen Y. K.; Yoshida, M.; MacMillan, D. W. C. Enantioselective Organocatalytic Amine Conjugate Addition. J. Am. Chem. Soc., 2006, 128(29): 9328-9329.
[15] Perdicchia D. and J?rgensen K. A. Asymmetric Aza-Michael Reactions Catalyzed by Cinchona Alkaloids. J. Org. Chem., 2007, 72(9): 3565-3568.
[16] Hiemstra H., Wynberg H. Addition of Aromatic Thiols to Conjugated Cycloalkenones, Catalyzed by Chiralβ-Hydroxy Amines. J. Am. Chem. Soc., 1981, 103(2): 417-430.
[17] Dinor P., Nielsen M., J?rgensen K. A. et al. Enantioselective Organocatalytic Conjugate Addition of N-Heterocycles toα,β-Unsaturated Aldehydes. Angew. Chem. Int. Ed., 2007, 46(12): 1983-1987.
[18] Ibrahem I., Rios R., Córdova A. et al. Organocatalytic Asymmetric 5-Hydroxyisoxazolidine Synthesis: A Highly Enantioselective Route toβ-Amino Acids. Chem. Commun., 2007, 2007(8): 849-851.
[19] Kiyosei T., Soumen M., Masataka I. Asymmetric Intramolecular Aza-Michael Reaction Using Environmentally Friendly Organocatalysis. Heterocycles, 2003, 59(1): 51-55.
[20] Yamamoto Y., Momiyama N., Yamamoto H. Enantioselective Tandem O-Nitroso Aldol/Michael Reaction. J. Am. Chem. Soc., 2004, 126(19): 5962-5963.
[21] Hayashi Y., Yamaguchi J., Koshino H. A Highly Active 4-Siloxyproline Catalyst for Asymmetric Synthesis. Adv. Synth. Catal., 2004, 346(12): 1435-1439.
[22] Itoh T., Yokoya, M., Miyauchi K. Total Synthesis of Ent-Dihydrocorynantheol by Using a Proline-Catalyzed Asymmetric Addition Reaction. Org. Lett., 2006, 8(8): 1533-1535.
[23] Bertelsen S., Diner P., J?rgensen K. A. Asymmetric Organocatalyticβ-Hydroxylation ofα,β-Unsaturated Aldehydes. J. Am. Chem. Soc., 2007, 129(6): 1536-1537.
[24] Xun S. D., Gaetan L., Zhang J. D. et al. Tuning the Electrical and Optical Properties of Dinuclear Ruthenium Complexes for Near Infrared Optical Sensing. Org. Lett., 2006, 8(8): 1697-1700.
[25] Saul G. C., Robert Z., Colin S. Preparation and Kinetics of Decomposition of a Bicyclic Aza Compound. A Novel Reduction. J. Am. Chem. Soc., 1961, 83(10): 2895-2900.
[26] Jacbos R. L. Oxidation of p-Toluenesulfonylhydrazide to 1,2-Di (p-toluenesulfonyl)hydrazine. J. Org. Chem., 1977, 42(3): 571-573.
[27] Lis R. and Marisca A. J. Methanesulfonanilides and the Mannich Reaction. J. Org. Chem., 1987, 52(19): 4377-4379.
[28] Sundberg R. J. and Laurino J. P. Cyclization of 2-[N-(Methylsulfonyl)anilino] -acetaldehyde Diethyl Acetals to Indoles. Evidence for Stereoelectronic Effects in Intramolecular Electrophilic Aromatic Substitution. J. Org. Chem., 1984, 49(2): 249-254.
[29] Teichert A., Jantos K., Studer A. et al. One-Pot Homolytic Aromatic Substitutions/HWE Olefinations under Microwave Conditions for the Formation of a Small Oxindole Library. Org. Lett., 2004, 6(20): 3477-3480.
[30] Jose B., Francisco J. F., Jose M. I. et al. 2-Arylallyl as a New Protecting Group for Amines, Amides and Alcohols. Chem. Commun., 2005, 2005(7): 933-935.
[31] Lei M., Tao, X. L. Wang Y. G. A Practical, Water-Soluble, Ionic Scavenger for the Solution-phase Syntheses of Amides. Helvetica Chimica Acta, 2006, 89(3):532-536.
[32] Koh K., Lee J. B., Ryu J. Photo-Fries Rearrangement of N-Arylsulfonamides to Aminoaryl Sulfone Derivatives. Tetrahedron, 2003, 59(39): 7651-7659.
[33] Ahmad R. M., Foad K., Ahmad R. M. et al. A Mild and Chemoselective Solvent-Free Method for the Synthesis of N-Aryl and N-Alkylsulfonamides. Letters in Organic Chemistry, 2006, 3(3): 235-241.
[34] Mansfeld M., Parik M. and Ludwig M. Effect of Para-Substitution on Dissociation of N-Phenylbenzenesulfonamides. Collect. Czech. Chem. Commun., 2004, 69(7): 1479-1490.
[35] Lyapkalo I. M., Reissig H. U., Schofer A. et al. Study of Unusually High Rotational Barriers about S-N Bonds in Nonafluorobutane-1-sulfonamides: The Electronic Nature of the Torsional Effect. Helvetica Chimica Acta, 2002, 85(12): 4206-4215.
[36] Lee B. K., Kim M. S., Leea W. K. et al. An Efficient Synthesis of Chiral Terminal 1,2-Diamines Using an Enantiomerically Pure [1-(10R)-Methylbenzyl] aziridine-2-yl]methanol. Tetrahedron, 2006, 62(35): 8393-8397.
[37] O’Neil I. A., Cleator E., Southern J. M. et al. The Stereospecific Addition of Hydroxylamines toα,β-Unsaturated Sulfones, Nitriles and Nitro Compounds. Tetrahedron Letters, 2001, 42(46): 8251-8254.
[38] Sabelle S., Lucet D., Mioskowski C. et al. Enantioselective Synthesis ofα-Amino Acids from Nitroalkenes. Tetrahedron Letters, 1998, 39(15): 2111-2114.
[39] Bowman R. K. and Johnson J. S. Lewis Acid Catalyzed Dipolar Cycloadditions of Imidates. J. Org. Chem., 2004, 69(24): 8537-8540.
[40] Liu J. T and Yao C. F. One-Pot Synthesis of Trans-β-Alkylstyrenes. Tetrahedron Letters, 2001, 42(35): 6147-6150.
[41] France S., Wack H., Taggi A. E. et al. Catalytic Asymmetricα-Chlorination of Acid Halides. J. Am. Chem. Soc., 2004, 126(13): 4245-4255.
[42] Li H. M., Wang Y., Deng L. et al. Highly Enantioselective Conjugate Addition of Malonate and Ketoester to Nitroalkenes: Asymmetric C-C Bond Formation with New Bifunctional Organic Catalysts Based on Cinchona Alkaloids. J. Am. Chem. Soc., 2004, 126(32): 9906-9907.
[43] Bikash P., Prasun K. P., Parasuraman J. et al. First Triphenylphosphine-Promoted Reduction of Maleimides to Succinimides. Synthesis, 2003, 2003(10): 1549-1552.
[44] Kishan P. H., Santosh B. M., Narshinha P. A. Cyanuric Chloride: Decent Dehydrating Agent for an Exclusive and Efficient Synthesis of Kinetically Controlled Isomaleimides. Tetrahedron, 2006, 62(5): 937-942.
[45] Antoioletti R., Bovicelli P., Malancona S. A New Route to 2-Alkenyl-1,3-dicarbonyl Compounds Intermediates in the Synthesis of Dihydrofurans. Tetrahedron, 2002, 58(3): 589-596.
[46] Lucet D.; Sabelle S.; Kostelitz O. et al. Enantioselective Synthesis ofα-Amino Acids and Monosubstituted 1,2-Diamines by Conjugate Addition of 4-Phenyl-2-oxazolidinone to Nitro Alkenes. Eur. J. Org. Chem., 1999, 1999(10): 2583-2591.
[47] Liu M. and Sibi M. P. Recent Advances in the Stereoselective Synthesis ofβ-Amino Acids. Tetrahedron, 2002, 58(40): 7991-8035.