Studies on copper-catalyzed aerobic reactions of N-H imines

Abstract

On investigating copper-catalyzed aerobic reactions of N-H imines, it was discovered that the iminyl copper species formed from reaction of Grignard reactions with carbonitriles, could undergo either C-H oxygenation or C-C bond cleavage depending on the starting material. The methylene C-H oxidation provides 1,2-diacylbenzenes, which could be further transformed into phthalazines and isoindolines, while a C-C bond cleavage provides carbonitriles using pivalonitrile as a cyanide source. Both transformations are aided by the oxidation of the iminyl copper species with diradical oxygen to form a peroxycopper intermediate, followed by oxidation or homolytic cleavage to effect oxidation and C-C bond cleavage respectively. Both reactions could provide a range of desired products in respectable yields.