Regioselective Conversion of Epoxides to Halohydrins by Titanium(IV) Halide-Lithium Halide Complex

Abstract

On treatment with titanium(IV) halide-lithium halide complex at low temperature, a series of epoxides [e.g., 1,2-epoxy-4-phenylbutane (1)] are regioselectively converted into the corresponding halohydrins resulting from an attack of halogen atom at the less substituted carbon atom. This procedure tolerates various alcohol protecting groups normally labile to aqueous acids, thus 2,3-epoxy alcohols allow the preparation of 3-halo-1,2-diols 6 which are selectively protected on only one hydroxy group.