Stereospecific preparation of trisubstituted allylic alcohols by alkene transfer from boron to zinc
作者:Morris Srebnik
DOI:10.1016/s0040-4039(00)74350-4
日期:1991.11
organozinc, to yield an equilibrium mixture, favoring the migration of alkenyl groups from boron to zinc. Addition of an aldehyde to the 2:3 reaction mixture, in the presence of 10 mol % N-methylpiperidine, results in the exclusive transfer of both alkenyl groups from zinc, furnishing diastereomerically pure trisubstituted double bnds in allylic alcohols in good to excellent yields.
(Z)-三烯基硼烷,(R 1 HC = CR 2)3 B,可以通过将相应的炔烃与BMS在THF中进行氢硼化而轻松制备,并在烃溶剂中与市售的二乙基锌迅速反应,以1:3或2:3或硼烷与有机锌的比例达到平衡,从而有利于烯基从硼向锌的迁移。在10 mol%N-甲基哌啶的存在下,向2:3反应混合物中添加醛会导致两个烯基从锌中排他性转移,从而在烯丙基醇中提供非对映异构纯的三取代双键,收率很好。