Pyrroles react with 1-acyl-2-bromoacetylenes at room temperature on silica to give 2-acyl-1,1-di(pyrrol-2-yl)ethenes as major products in yields of up to 60%. Under reaction conditions employed, the intermediates (E)-2-(2-acyl-1-bromoethenyl)pyrroles (3-11% isolated yields) either readily exchange the bromine atom for the pyrrole molecule or eliminate HBr to afford 2-(2-acylethynyl)pyrroles, which can be isolated in 9-22% yields by chromatography of the reaction mixture on Al2O3.
室温下,
吡咯与 1-酰基-2-
溴乙炔在
二氧化硅上发生反应,生成 2-酰基-1,1-二(
吡咯-2-基)
乙烯作为主要产物,产率高达 60%。在所采用的反应条件下,中间产物 (E)-2-(2-acyl-1-bromoethenyl)pyrroles (分离收率为 3-11%)要么很容易将
溴原子交换为
吡咯分子,要么消除 HBr 生成 2-(2-acylthynyl)pyrroles,通过在
Al2O3 上对反应混合物进行
色谱分析,可分离出收率为 9-22%的 2-(2-acylthynyl)pyrroles。