Palladium-catalyzed cycloisomerization of ( Z )-(2-en-4-ynyl)amines: a new synthesis of substituted pyrroles
作者:Bartolo Gabriele、Giuseppe Salerno、Alessia Fazio、Maria R Bossio
DOI:10.1016/s0040-4039(00)02206-1
日期:2001.2
(Z)-(2-En-4-ynyl)amines 1 bearing an internal triple bond undergo smooth cycloisomerization into pyrroles 2 in the presence of catalytic amounts of PdCl2 in conjunction with KCl at 25–100°C in anhydrous N,N-dimethylacetamide. When the triple bond is terminal, spontaneous uncatalyzed cyclization to the corresponding pyrroles takes place.
A general and regioselective synthesis of substituted pyrroles 2 by cycloisomerization of readily available (Z)-(2-en-4-ynyl)amines 1 is reported. Spontaneous cycloisomerization leading to 2 occurred in the course of preparation of enynamines bearing a terminal triple bond or a triple bond substituted with a phenyl or a CH2OTHP group. When the triple bond was substituted with an alkyl or alkenyl group