Synthesis of NH -3-phenylsulfanyl- and NH -3-benzylsulfanyl-azetidinones from 1-phenylsulfanyl- or 1-benzylsulfanyl-3-aza-1,3-dienes

A simple, modular synthesis of substituted pyridines

A simple, modular method to prepare highly substituted pyridines is disclosed. The method employs a cascade reaction comprising (1) a novel N-iminative, Cu-catalyzed cross-coupling of alkenylboronic acids at the N-O bond of alpha,beta-unsaturated ketoxime O-pentafluorobenzoates, (2) electrocyclization of the resulting 3-azatriene, and (3) air oxidation affording highly substituted pyridines in moderate to excellent isolated yields (43-91%). Starting materials are readily available, and functional group tolerance is very good.