Enantioselective addition of diethylzinc to aldehydes catalyzed by chiral amino alcohols. Substituent effect and nonlinear effect
作者:Takahiko Ohga、Satoshi Umeda、Yasuhiro Kawanami
DOI:10.1016/s0040-4020(01)00423-9
日期:2001.6
series of chiral β-amino alcohols derived from (S)-leucine, valine, and phenylalanine have been synthesized and evaluated as chiral catalysts for the enantioselective addition of diethylzinc to aldehydes. The β-amino alcohol (1c) possessing a isobutyl substituent and two phenethyl substituents on the carbinol carbon atom was found to be an efficient and optimal ligand to catalyze the diethylzinc addition
合成了一系列新的衍生自(S)-亮氨酸,缬氨酸和苯丙氨酸的手性β-氨基醇,并将其作为手性催化剂用于将二乙基锌对映异构地加成到醛中。发现在甲醇碳原子上具有异丁基取代基和两个苯乙基取代基的β-氨基醇(1c)是高效且最佳的配体,其具有高对映选择性(至多97%ee)和良好的收率催化二乙基锌的加成。此外,在对映选择性催化中观察到强(+)非线性效应(不对称扩增),通过在20%ee中使用配体1c提供高水平的对映体选择(93%ee)。