Modular synthesis of pyrrolo[2,1-b]thiazoles and related monocyclic pyrrolo structures

摘要

A modular synthesis of selectively-substituted pyrrolo[2,1-b]thiazoles (Δ~6 isomeric form) has been implemented, involving a distinctive bicyclization reaction of a mucobromic acid derivative followed by a Suzuki-Miyaura coupling. A novel process of Δ~6 to Δ~7 isomerization of the pyrrolothiazole structure was uncovered that appears to involve a 1,4-addition-1,2-elimination mechanism. Preparation of 1,5-dihydropyrrol-2-one structures, selectively substituted at the 3- and 4-positions, was also achieved using the mucobromic acid synthon in a reductive amination process.