Formation of 2,2′-Diacyl-9,9′-bifluorenylidene Isomers from 2-Acyl-9-bromofluorene and Base-Catalyzed Isomerization of the Formed Alkenes
作者:Masahiro Minabe、Ayumi Yamazaki、Toshinobu Imai、Takumi Takanezawa、Michinori Karikomi
DOI:10.1246/bcsj.79.1758
日期:2006.11
formation of 2,2'-diacyl-9,9'-bifluorenylidene from 2-acyl-9-bromofluorene. The E-isomer was obtained mainly when the acyl group was a short alkyl chain, such as an acetyl group, and Z-isomer was isolated predominantly when a long acyl chain such as stearoyl group was attached. 9,9'-Bifluorenylidene was formed via anti elimination of hydrogen bromide from the intermediate 9-bromo-9,9'-bifluorenyl. This
我们研究了 2,2'-diacyl-9,9'-bifluorenylidene 从 2-acyl-9-bromofluorene 的形成。E-异构体主要在酰基为短烷基链(如乙酰基)时获得,而Z-异构体主要在连接长酰基链(如硬脂酰基)时分离。9,9'-二芴基是通过从中间体 9-溴-9,9'-二芴基中反消除溴化氢而形成的。这表明 2,2'-二酰基-9,9'-二芴基的立体化学由 9-溴-9,9'-二芴基异构体的构型决定,Z-和 E-异构体的比例为 1: 1. 9,9'-二芴基的轻松碱催化 Z/E 异构化跟随烯烃的形成,根据酰基侧链的长度显示出不同的立体选择性。另一方面,2,2'-二酰基-9,9'-二芴基的热处理提供了约。Z-异构体和 E-异构体的 1:1 混合物,表明热异构化通过与碱催化异构化不同的途径发生。