Efficient Mono- and Dilithiation of 2-Bromo-1,1-diphenylethene with n-Butyllithium/Tetramethylethylenediamine
作者:Sergei M. Korneev、Dieter E. Kaufmann
DOI:10.1055/s-2002-20963
日期:——
Lithiation of 2-bromo-1, 1-diphenylethene (2) with «-butyllithium or tert-butyllithium/tetramethylethylenediamine (TMEDA) in pentane at -100 °C effects a halogen-lithium exchange to give 2-lithio-1,1-diphenylethene (3) exclusively, which reacts with electrophiles to provide 2-substituted-1,1-diphenylethenes 5-8 in high yields. Further lithiation of the monolithium derivative 3 with n-butyllithium/TMEDA
2-溴-1, 1-二苯基乙烯 (2) 与 -100 °C 戊烷中的«-丁基锂或叔丁基锂/四甲基乙二胺 (TMEDA) 进行锂化反应,发生卤素-锂交换,生成 2-锂硫-1,1-二苯基乙烯 (3) 仅与亲电试剂反应以高产率提供 2-取代的 1,1-二苯基乙烯 5-8。单锂衍生物 3 与正丁基锂/TMEDA 的进一步锂化导致 Z 位苯环的直接邻位锂化得到二锂衍生物 9,其在用亲电试剂叔叔处理时形成二取代的乙烯 11-13 或杂环 15-17 -丁基锂/TMEDA 对第二个锂化步骤无效。