REGIOSELECTIVE FUNCTIONALIZATION OF cis-BICYCLOOCTENONE DERIVATIVES. OXYMERCURATION/REDUCTION VERSUS HYDROBORATION/OXIDATION. ACETAL GROUPS AS REGIO- AND STEREOSELECTIVE CONTROL ELEMENTS

Article abstract of DOI:10.1246/cl.1984.775

Cyclic acetal groups at the position 8 of the cis-bicyclo<3.3.0>octane system may act as regio- and stereoselective control elements, respectively, in hydroboration and oxymercuration reactions.Whereas the regioselectivity observed in hydroborations must be ascribed to homoallylic inductive effects, and leads predominantly to exo, 1,3-bifunctional relationships, the effect of acetal group in oxymercuration is mainly stereoselective due to coordination of mercury acetate with the nonbonding electron pairs of the endo-oxygen atom of the acetal group, and leads predominantly to exo, 1,4-bifunctional relationships.