Electrochemically initiated intermolecular C-N formation/cyclization of ketones with 2-aminopyridines: an efficient method for the synthesis of imidazo[1,2-a]pyridines

Electrochemical intermolecular C-N formation/cyclization of ketones with 2-aminopyridines using catalytic hydriodic acid as the redox mediator was developed, providing imidazo[1,2-a]pyridines under more environmentally benign conditions. The reaction proceeds in a simple undivided cell, using low toxic ethanol as the solvent, without external oxidants, and exhibits high atom economy. A variety of ketones including acetophenones, unsatruated and alkyl ketones are amenable to this reaction, affording the corresponding products in moderate to excellent yields. A three-component tandem reaction realizing C-N, C-S/C-Se bond formation can also be achieved under standard conditions.