Synthetic studies of huperzine A and its fluorinated analogues. 1. Novel asymmetric syntheses of an enantiomeric pair of huperzine A
作者:Satoru Kaneko、Toshiharu Yoshino、Tadashi Katoh、Shiro Terashima
DOI:10.1016/s0040-4020(98)00227-0
日期:1998.5
carrying chiral ferrocenylphosphine ligands (max. 64% ee, 3+7→8, Scheme 3) as the key steps. Recrystallization of the partially optically active tricycles (+)- and (−)-6 derived from the products of the asymmetric reactions, readily provided the corresponding optically pure samples (both >99% ee). According to the reported method, the total synthesis of an enantiomeric pair of 1 [(−)- and (+)-1] was completed
石杉碱甲的对映异构体对的合成是通过两种方法完成的,该方法采用串联金鸡纳生物碱促进β-酮酸酯3与甲基丙烯醛的不对称迈克尔加成/醛醇缩合反应(4)(最大64%ee,3) + 4→5 ,方案2)和3的不对称双环环化反应与2-手性二茂铁基膦配体的钯催化剂催化的2-乙酸-1,3-丙二醇二乙酸酯(7)(最大64%ee,3 + 7→8 ,方案) 3)作为关键步骤。部分旋光的三环(+)-和(-)- 6的重结晶衍生自不对称反应产物的化合物,很容易提供相应的光学纯样品(均> 99%ee)。根据报道的方法,对映异构体对的全合成1 - [( - ) -和(+) - 1 ]完成与光学纯(+)起始-和( - ) - 6(方案4)。