Control of regio- and stereoselectivity in electrophilic addition reactions of allenes*
Shengming Ma
Laboratory of Molecular Recognition and Synthesis, Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027 and State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, P. R. China
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.
Keywords: allenes; selectivity; electrophilic addition; halohydroxylation; 1,2-shift.
*Paper based on a presentation at the 16th International Conference on Organic Synthesis (ICOS-16), 11-15 June 2006, Mérida, Yucatán, México. Other presentations are published in this issue, pp. 153-291.