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

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. J. Heterocyclic Chem., (2011).