Highly Regioselective and Stereoselective Haloazidation of Alkynes Mediated by a Halide-Bridged Charge-Transfer Complex

More than 100 years after the initial report of alkene halogenation-azidation reactions, a general method for haloazidation of alkynes has remained elusive, primarily due to the higher bond dissociation energy of alkynes and inherent stereoselectivity challenges. Herein, we develop a versatile strategy for the azidohalogenation of alkynes using IBA-N₃ and halogen salts, facilitated by Coulombic and cation-π interactions. This transformation features a broad substrate scope, operational simplicity, and excellent regio- and stereoselectivity, providing efficient access to diverse functionalized vinyl azido-halogen compounds through iodoazidation, bromoazidation, and chlorazidation of alkynes.