Iodine-Promoted Thioylation and Dicarbonylation of Enaminone -C Sites: Synthesis of Fully Substituted Thiazoles via C=C Bond Cleavage

A novel iodine-promoted difunctionalization of alpha-C sites in enaminones was demonstrated as a means of synthesizing a variety of fully substituted thiazoles by constructing C-C(CO), C-S, and C-N bonds. This transformation allows the realization of enaminones as unusual aryl C2 synthons and simultaneously allows the thioylation and dicarbonylation of alpha-C sites. A preliminary mechanistic study was performed and indicated that the cleavage of C=C bonds in enaminones involves a bicyclization/ring-opening and oxidative coupling sequence.