Enantioselective conjugate addition of ketones to β-nitrostyrenes catalyzed by 1,2-amino alcohol-derived prolinamides
摘要:
Various L-prolinamides 14, prepared from L-proline and chiral beta-amino alcohols, are active bifunctional catalysts for the direct nitro-Michael addition of ketones to beta-nitrostyrenes. In particular, catalyst 14e prepared from L-proline and (1S,2R)-cis-1amino-2-indanol exhibits the highest catalytic performance working in polar aprotic solvents such as NMP. High syn-diastereoselectivities (up to 94% de) and good enantioselectivities (up to 80% ee) were obtained at rt. (c) 2006 Elsevier Ltd. All rights reserved.
l-proline amide moiety and a terminal hydroxyl for catalyzing direct asymmetric aldol reactions of aldehydes in neat acetone are designed and prepared. Catalyst 3d, prepared from l-proline and (1S,2S)-diphenyl-2-aminoethanol, exhibits high enantioselectivities of up to 93% ee for aromaticaldehydes and up to >99% ee for aliphatic aldehydes. A theoretical study of transition structures demonstrates the important
设计并制备了含有 l-脯氨酸酰胺部分和末端羟基的新型有机分子,用于催化醛在纯丙酮中的直接不对称羟醛反应。由 l-脯氨酸和 (1S,2S)-二苯基-2-氨基乙醇制备的催化剂 3d 对芳香醛的对映选择性高达 93% ee,对脂肪醛的对映选择性高达 >99%。过渡结构的理论研究证明了催化剂中末端羟基在立体识别中的重要作用。我们的研究结果表明,在设计用于直接不对称醛醇反应和相关转化的新型有机催化剂方面采用了一种新策略,因为在设计中可能会采用大量含有多氢键供体(例如肽)的手性资源。