Palladium-catalyzed Csp2–H carbonylation of aromatic oximes: selective access to benzo[d][1,2]oxazin-1-ones and 3-methyleneisoindolin-1-ones

Abstract

A highly selective palladium-catalyzed carbonylation of Csp²–H bonds with aromatic oximes for the synthesis of benzo[d][1,2]oxazin-1-ones and 3-methyleneisoindolin-1-ones has been developed. Interestingly, we found that the N–OH group of the oximes could be used as a directing group and/or an internal oxidant under different conditions. This transformation is supposed to proceed through a hydroxyl-directed ortho-Csp²–H carbonylation or activation of vinyl Csp²–H bond/ortho-Csp²–H carbonylation process. The uses of readily available starting materials, atmospheric pressure of carbon monoxide, as well as operational simplicity make this practical and atom-economical method particularly attractive.