Control of regio- and stereoselectivity in electrophilic addition reactions of allenes

Abstract

The halohydroxylation reaction of 1,2-allenyl sulfoxides exhibits E-selectivity while those of analogous sulfides and selenides show Z-selectivity. Rationales for the stereoselectivities are proposed. The reaction of 2,3-allenols with X+ affords 3-halo-2,5-dihydrofurans or 3-halo-3-enals depending on the nature of the alcohols. © 2007 IUPAC.