Halogen Bond-Activated Visible-Light-Mediated Regioselective C–H Arylation of 2-Phenylimidazo-[1,2-<i>a</i>]pyridines
Imran Kazi, Anuradha Nandy, R. Panner Selvam, Govindasamy Sekar
Abstract
An efficient method for transition metal-free halogen bond-assisted regioselective C–H arylation of 2-phenylimidazo-[1,2-a]pyridines under visible-light condition has been developed. The halogen bond between an aryl halide and base KOtBu initiates an electron transfer process and generates an aryl radical, which catalyzes its coupling with 2-phenylimidazo-[1,2-a]pyridines to give arylated products in good yield. Several control experiments, density functional theory calculations, and ultraviolet–visible analysis indicate the presence of a halogen bond between an aryl halide and KOtBu. This methodology has been successfully utilized to synthesize antileishmanial agents.
Topics & Concepts
ChemistryRegioselectivityArylHalogen bondHalogenHalideYield (engineering)PhotochemistryCombinatorial chemistryDensity functional theoryVisible spectrumMedicinal chemistryComputational chemistryCatalysisOrganic chemistryAlkylPhysicsMaterials scienceMetallurgyOptoelectronicsCatalytic C–H Functionalization MethodsSulfur-Based Synthesis TechniquesRadical Photochemical Reactions