Chiral Primary−Tertiary Diamine Catalysts Derived From Natural Amino Acids for <i>syn</i>-Aldol Reactions of Hydroxy Ketones
作者:Jiuyuan Li、Sanzhong Luo、Jin-Pei Cheng
DOI:10.1021/jo802557p
日期:2009.2.20
A series of primary-tertiary diamine catalysts were designed and synthesized from primary natural amino acids. Application of these new chiral catalysts in direct aldol reactions of α-hydroxyketones showed very good catalytic activity (up to 97% yield) and high syn selectivity (up to syn/ anti = 30:1, 99% ee).
从伯天然氨基酸设计合成了一系列伯叔二胺催化剂。这些新的手性催化剂在α-羟基酮的直接醛醇缩合反应中的应用显示出非常好的催化活性(高达97%的收率)和高的合成选择性(高达syn / anti = 30:1,99%ee)。
Highly Enantioselective Co-Catalytic Direct Aldol Reactions by Combination of Hydrogen-Bond Donating and Acyclic Amino Acid Catalysts
Highlyenantioselectiveco-catalyticdirectaldolreactions by a combination of simple hydrophobic acyclicaminoacid and hydrogen-bonddonatingcatalysts are presented. The corresponding aldol products are formed in high yields with high regio-, diastereo- (anti or syn) and enantioselectivity (up to 99.5:0.5 er). The catalyst loadings can be decreased to as little as 2 mol%.
Highly Enantioselective Organocatalytic<i>syn</i>- and<i>anti</i>-Aldol Reactions in Aqueous Medium
作者:Monika Raj、Gopal S. Parashari、Vinod K. Singh
DOI:10.1002/adsc.200900122
日期:2009.6
Abstractmagnified imageWe have synthesized chiral diamines that efficiently catalyze the syn‐ and anti‐aldol reactions in aqueous medium with high diastereo‐ and enantioselectivities. The product, thus obtained, was further reduced selectively to give syn‐configured 1,2,3‐triol, an important subunit present in various monosaccharides and natural products such as (+)‐boronolide.
Enantioselective Aldol Condensations Catalyzed by Poly(ethylene glycol)-Supported Proline
water-compatible amino-acid-based catalysts was explored in the development of diastereo- and enantioselectivedirectaldolreactions of a broad range of substrates. Chiral C2-symmetrical proline- and valine-based amides and their ZnII complexes were designed for use as efficient and flexible chiral catalysts for enantioselectivealdolreactions in water, on water, and in the presence of water. The presence of