A Versatile Chemo-Enzymatic Route to Enantiomerically Pure β-Branched α-Amino Acids
作者:Geoffrey J. Roff、Richard C. Lloyd、Nicholas J. Turner
DOI:10.1021/ja049499d
日期:2004.4.1
A series of diastereoisomers of beta-methyl-beta-phenylalanine analogues 1a-f have been prepared in enantiomerically pure form using a combination of chemo- and biocatalysis. Starting from l-threonine methyl ester 2, a range of beta,beta-disubstituted didehydroamino acids were obtained as their (Z)-isomers 6a-f. Asymmetric hydrogenation of these alkenes, using either the [Rh(R,R)-Et-DuPhos(COD)]BF4
一系列β-甲基-β-苯丙氨酸类似物1a-f 的非对映异构体已使用化学和生物催化的组合以对映体纯形式制备。从 l-苏氨酸甲酯 2 开始,获得了一系列 β,β-二取代的双脱氢氨基酸,作为它们的 (Z)-异构体 6a-f。这些烯烃的不对称氢化,使用 [Rh(R,R)-Et-DuPhos(COD)]BF4 或 [Rh(S,S)-Et-DuPhos(COD)]BF4 催化剂,然后水解得到两个β-支链氨基酸的四组可能的非对映异构体。随后的立体反转,使用立体选择性氨基酸氧化酶与非选择性还原剂组合,提供剩余的两组非对映异构体。