Copper‐Catalyzed Intermolecular Oxidative Cyclization of Halo‐ alkynes: Synthesis of 2‐Halo‐substituted Imidazo[1,2‐a]pyridines, Imidazo[1,2‐a]pyrazines and Imidazo[1,2‐a]pyrimidines

摘要: An efficient copper-catalyzed method for the synthesis of 2-haloimidazopyridines with aminopyridines and haloalkynes using molecular oxygen as oxidant in a one-pot manner has been developed. In this process, reaction appears to be very general suitable construction variety 2-halo-substituted imidazopyridines, imidazopyrazines imidazopyrimidines. The intermolecular oxidative diamination was achieved first time. Importantly, mild conditions conversion alkyl-substituted are great improvements over existing methods. Moreover, resultant 2-haloimidazo[1,2-a]pyridines could efficiently converted other functionalized imidazopyridine products via substitution, coupling reactions transformations, which further indicates potential applications synthetic pharmaceutical chemistry.