Double Deprotonation of Acetylenic Oxiranes: Synthesis of Allenic Ketones through Dilithio Ynenolates
摘要:
The double deprotonation of acetylenic oxiranes gives allenic ketones through the 1,2-H or 1,2-Ar shift on the transient oxiranyl dianion intermediates. The resulting dilithium ynenolates give allenic ketones upon hydrolysis or can be quenched with various electrophiles.
Reaction of dialkylzincs with lithiated acetylenic epoxides is described to give zincates that undergo a 1,2-metallate rearrangement by an anti-SN2′ pathway. This rearrangement occurs with the transfer of an alkyl or a silyl group affording allenylzinc intermediates. Allenic and/or homopropargylic alcohols are obtained upon hydrolysis. Quenching the reaction mixture with aldehydes or ketones is shown
描述了二烷基锌与锂化的炔属环氧化物的反应以通过反-S N 2'途径产生经历1,2-金属盐重排的锌酸盐。这种重排通过烷基或甲硅烷基的转移发生而得到烯丙基锌中间体。烯丙和/或均丙醇在水解时获得。显示用醛或酮淬灭反应混合物以立体选择性方式获得2-炔基-1,3-二醇。