Recent Progress in the Asymmetric Intermolecular Halogenation of Alkenes

As a long-standing problem in organic chemistry, and a very useful transformation in organic synthesis, the catalytic asymmetric halogenation of alkenes has only recently been reported. New catalysts and novel approaches have been developed for asymmetric halocyclizations. Although mechanism studies indicated the asymmetric intermolecular halogenation of alkenes is more difficult, important breakthroughs have also been achieved. In this review article, the scope, mechanism, and limitations of recently developed catalytic asymmetric intermolecular halogenation of alkenes are described. 1 Introduction 2 Asymmetric Intermolecular Halogenation of Alkenes 2.1 Asymmetric Halogenation of α,β-Unsaturated Compounds 2.2 Asymmetric Halogenation of Allylic Alcohols 2.3 Asymmetric Halogenation of Enecarbamates and Enamides 2.4 Asymmetric Halogenation of Allylic Sulfonamides 2.5 Asymmetric Halogenation of Unfunctionalized Alkenes 3