Cobalt-promoted synthesis of sulfurated oxindoles radical annulation of -arylacrylamides with disulfides.

An efficient radical annulation of -arylacrylamides with disulfides is developed for the synthesis of sulfurated oxindoles. The reaction occurs in a facile manner using CoBr as both an initiator and a promoter for the first time and (NH)SO as the oxidant. By controlling the CoBr/(NH)SO ratio, a wide range of sulfurated and brominated/sulfurated oxindoles are selectively prepared in good to excellent yields. The present protocol is simple and highly atom economical, and can tolerate a broad range of substrates.