Decarbonylative Liebeskind-Srogl Reductive Pyridination of Aromatic Thioesters by Cobalt Catalysis.

Palladium-catalyzed nondecarbonylative Liebeskind-Srogl reactions of aryl thioesters have evolved as a powerful tool for the synthesis of ketones. In sharp contrast, decarbonylative Liebeskind-Srogl coupling remains a huge challenge. Herein, we present a cobalt-catalyzed decarbonylative Liebeskind-Srogl reductive pyridination of aromatic thioesters with pyridinyl phosphonium salts. The catalytic protocol provides an alternative route for the efficient synthesis of C4-arylated pyridines from easily available starting materials with wide substrate scope, good functional group tolerance, and chemoselectivity.