Diastereoselective addition of allylmetal compounds to imines derived from (S)-1-phenylethanamine
作者:Giuseppe Alvaro、Carla Boga、Diego Savoia、Achille Umani-Ronchi
DOI:10.1039/p19960000875
日期:——
diastereoselectivity in the addition of allylmetal compounds to imines derived from aldehydes and (S)-1-phenylethanamine is affected by the nature of the imine and of the metal. Allyl-BBN, -MgX, -ZnBr, -Cu, and diallylcuprate attacked the Si face of the imine derived from 2-methylpropanal. Conversely, the Re face of aromatic aldimines was generally attacked, but the behaviour of the magnesium reagent was variable
亚胺和金属的性质影响在将烯丙基金属化合物添加到衍生自醛和(S)-1-苯基乙胺的亚胺中的烯丙基金属化合物中的不对称感应和非对映选择性的程度。烯丙基-BBN,-MgX,-ZnBr,-Cu和二烯丙基丙二酸酯攻击衍生自2-甲基丙醛的亚胺的Si面。相反,一般会侵蚀芳族醛亚胺的Re面,但是镁试剂的行为是可变的。烯丙基-BBN和二烯丙基铜酸酯(在-78°C时高达98%)与脂族和芳族亚胺都获得了最佳结果。然而,使用allylzinc溴化物和烯丙基(二氯)iodotin的是优选与二齿吡啶-2-亚胺(DE 70%,再面部除法)。手性助剂的裂解(碳-甲醇上的甲酸甲铵盐,65°C,2 h)是区域选择性的,伴随不饱和链的氢化,仅发生在通过(S)-2,5-反应得到的二苄基胺上二甲氧基苯扎尔二胺与烯丙基-BBN(de 94%)和二价铜酸盐(de 99%)。这样可以快速有效地合成(R)-(+)-1-(2,5-二甲氧基苯基