Synthesis of Vicinal Halohydrins via Dynamic Kinetic Resolution

Significance

Dynamic kinetic resolution (DKR) is the most efficient resolution technique and has been applied to the formation of vicinal halohydrins in this report. The use of transfer hydrogenation conditions with the Noyori-Ikariya catalyst (I) and either HCO₂H-Et₃N or HCO₂Na as the hydrogen donor gave excellent results for a number of halo-indanones and -tetralones. Depending on the particular substrate, different solvent/hydrogen donor systems were used. Chlorine- and ­fluorine-containing compounds usually required HCO₂H-Et₃N while bromine-containing compounds showed higher success with a HCO₂Na-TBABr system. Both diastereo- and enantioselectivities are excellent.