I2O5-Mediated Iodocyclization Cascade of N-(1-Arylallyl)pyridine-2-amines with Concomitant C=C Bond Cleavage: A Synthesis of 3-Iodoimidazo[1,2-a]pyridines

A facile method for the synthesis of 3-iodoimidazo[1,2-a]pyridines has been successfully developed involving an I2O5-mediated iodocyclization cascade of N-(1-arylallyl)pyridin-2-amines with concomitant C=C bond cleavage. Preliminary mechanistic studies reveal that this protocol might undergo an oxidative cyclization/decarboxylation/iodination sequence in which I2O5 is used as both an oxidant and an iodine source. The present protocol has advantages of wide substrate scope, simple operation, and metal-free conditions.