Enantioselective cyclopropanation of allylic alcohols: the effect of zinc iodide

The presence of zinc iodide during the catalytic enantioselective cyclopropanation of allylic alcohols enhanced the reaction rates in bis-methanesulfonamide. The effects of zinc iodide on the bis-methanesulfonamide-catalyzed reaction of allylic alcohols in the presence of bis(iodomethyl)zinc reagents were mediated by reagent modification via a Schenk equilibrium. Furthermore, the presence of zinc iodide induced the formation of a highly reactive (iodomethyl)zinc iodide.