Recent Advances in Catalytic Asymmetric Syntheses of Functionalized Heterocycles via Halogenation/Chalcogenation of Carbon‐Carbon Unsaturated Bonds

Halogen (fluorine, chlorine, bromine, iodine) or chalcogen (sulfur, selenium)‐containing heterocycles are widely recognized as key building blocks in many natural products and bioactive targets. Catalytic asymmetric halogenation/chalcogenation of carbon‐carbon unsaturated bonds via onium ion transformations are efficient methods to obtain diverse chiral heterocyclic backbones. In the past few years, catalytic enantioselective versions of halo/thio/seleno‐functionalizations with various halogen and chalcogen electrophiles have experienced constant development. This review highlights those advances in preparing functionalized heterocycles promoted by chiral organocatalysts or metal‐based catalysts. magnified image