钌-路易斯酸催化二烯与α,β-不饱和酮之间的不对称狄尔斯-阿尔德反应。

Ruthenium-Lewis acid catalyzed asymmetric Diels-Alder reactions between dienes and alpha,beta-unsaturated ketones.

作者信息

Rickerby Jenny, Vallet Martial, Bernardinelli Gerald, Viton Florian, Kündig E Peter

机构信息

Department of Organic Chemistry, Sciences II, University of Geneva, 30 Quai Ernest-Ansermet, CH1211, Geneva 4, Switzerland.

出版信息

Chemistry. 2007;13(12):3354-68. doi: 10.1002/chem.200600851.

DOI:10.1002/chem.200600851

PMID:17226865

Abstract

The complex [Ru(Cp)(R,R-BIPHOP-F)(acetone)][SbF(6)], (R,R)-1 a, was used as catalyst for asymmetric Diels-Alder reactions between dienes (cyclopentadiene, methylcyclopentadiene, isoprene, 2,3-dimethylbutadiene) and alpha,beta-unsaturated ketones (methyl vinyl ketone (MVK), ethyl vinyl ketone, divinyl ketone, alpha-bromovinyl methyl ketone and alpha-chlorovinyl methyl ketone). The cycloaddition products were obtained in yields of 50-90 % and with enantioselectivities up to 96 % ee. Ethyl vinyl ketone, divinyl ketone and the halogenated vinyl ketones worked best and their reactions with acyclic dienes consistently provided products with >90 % ee. alpha-Chlorovinyl methyl ketone performed better than alpha-bromovinyl methyl ketone. The reaction also provided a [4.3.1]bicyclic ring system in 95 % ee through an intramolecular cycloaddition reaction. Crystal structure determinations of [Ru(Cp)((S,S)-BIPHOP-F)(mvk)][SbF(6)], (S,S)-1 b, and [Ru(Cp)((R,R)-Me(4)BIPHOP-F)(acrolein)][SbF(6)], (R,R)-2 b, provided the basis for a rationalization of the asymmetric induction.

摘要

配合物[Ru(Cp)(R,R - BIPHOP - F)(丙酮)][SbF₆]，即(R,R)-1 a，被用作二烯（环戊二烯、甲基环戊二烯、异戊二烯、2,3 - 二甲基丁二烯）与α,β - 不饱和酮（甲基乙烯基酮（MVK）、乙基乙烯基酮、二乙烯基酮、α - 溴乙烯基甲基酮和α - 氯乙烯基甲基酮）之间不对称狄尔斯 - 阿尔德反应的催化剂。环加成产物的产率为50 - 90%，对映选择性高达96% ee。乙基乙烯基酮、二乙烯基酮和卤代乙烯基酮的反应效果最佳，它们与无环二烯的反应始终能提供对映体过量>90% ee的产物。α - 氯乙烯基甲基酮的表现优于α - 溴乙烯基甲基酮。该反应还通过分子内环加成反应以95% ee的对映体过量得到了一个[4.3.1]双环体系。[Ru(Cp)((S,S)-BIPHOP - F)(mvk)][SbF₆]，即(S,S)-1 b，和[Ru(Cp)((R,R)-Me₄BIPHOP - F)(丙烯醛)][SbF₆]，即(R,R)-2 b的晶体结构测定为不对称诱导的合理化提供了依据。