Addition of Dilithio Derivatives of N-Monosubstituted Propanamides to Aldehydes: Stereochemistry, Scope and Limitations
作者:David E. Lewis、Glen C. Gullickson、Mushtaq A. Khan、Jessica A. Walters、Russell G. Baughman
DOI:10.1055/s-2005-872167
日期:——
at 0 °C. Addition of the dilithio compound to aldehydes results in a mixture of the syn and anti aldols in near equal quantities, and in the recovery of up to 30% of the unreacted amide. The reaction outcome is essentially unaffected by time and temperature. Added zinc chloride changes the isomer ratio, but reduces chemical yields dramatically. The results are interpreted in terms of addition through
N-单取代丙酰胺的二硫代衍生物形成为立体异构体的混合物,其中 Z(O)-异构体在 THF-Et 2 O 中在 0 °C 下的酰胺和丁基锂之间的反应显着有利于 Z(O)-异构体。将二锂化合物添加到醛中会产生几乎等量的顺醛醇和反醛醇的混合物,并且可以回收高达 30% 的未反应酰胺。反应结果基本上不受时间和温度的影响。添加氯化锌会改变异构体比例,但会显着降低化学收率。结果解释为通过三个异构齐默尔曼-特拉克斯勒型过渡态的加法。