Palladium-Catalyzed Oxidant Dependent Switchable Aza-Wacker Cyclization and Oxidative Dimerization of Benzimidates.

An oxidant dependent switchable palladium-catalyzed synthesis of 1,3-oxazines and benzohydrazonates (azines) from O -homoallyl benzimidates has been developed. The reaction involved aza-Wacker-type intramolecular cyclization of O -homoallyl benzimidates with Cu(OAc) 2 as oxidant under Pd-catalysis to deliver 4-methylene-1,3-oxazines, whereas dimerization of O -homoallyl benzimidates with K 2 S 2 O 8 as oxidant resulted remarkably in benzohydrazonates (azines). The reaction is atom economic with an easily operational procedure for divergent synthesis of important scaffolds.