Silver-catalyzed cyclization of N-(prop-2-yn-1-yl)pyridin-2-amines

We report herein the silver-catalyzed cycloisomerization of readily available N-(prop-2-yn-1-yl)pyridine-2-amines as a new and practical method for the synthesis of differently substituted 3-methylimidazo[1,2-a]pyridines. The isomerization reactions proceeded under mild reactions conditions to give good yields and excellent regioselectivity. A DFT-based mechanistic analysis is also reported. The silver-catalyzed cycloisomerization of readily available N-(prop-2-yn-1-ylamino)pyridines is a new and practical method for the synthesis of differently substituted 3-methylimidazo[1,2-a]pyridines, suitable intermediates for further synthetic transformations and modulation, that proceeds under mild reaction conditions to give good-to-high yields and excellent regioselectivity.