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.