Asymmetric synthesis via acetal templates. 12. Highly diastereoselective coupling reactions with a ketene acetal. An efficient, asymmetric synthesis of R-(+)-α-lipoic acid
作者:John D. Elliott、John Steele、William S. Johnson
DOI:10.1016/s0040-4039(00)98830-0
日期:1985.1
2 to generate β-alkoxycarboxylates in which the new asymmetric center is formed with excellent diastereoselection. β-hydroxycarboxylic acids of high ee result from removal of the chiral auxiliary. The procedure has been applied to the synthesis of R-(+)-α-lipoic acid 10.
TiCl 4催化手性乙缩醛1与1-t-丁氧基-1-t-丁基二甲基甲硅烷基氧化乙烯2的基本定量偶联,生成β-烷氧基羧酸酯,其中新的不对称中心形成,具有出色的非对映选择性。高ee的β-羟基羧酸是由于手性助剂的去除而产生的。该程序已应用于合成R-(+)-α-硫辛酸10。