Effect of Silica Gel on the Benzenesulfinic Acid Catalyzed Isomerization of Vinylsilanes. Formation of Silyl Benzenesulfinate

Article abstract of DOI:10.1021/jo00271a020

A new method for the isomerization of (Z)-vinylsilanes into the E isomers has been developed.In contrast to the facile protodesilylation of vinylsilanes with arenesulfinic acids, use of silica gel as an additive in the reaction of vinylsilanes with benzenesulfinic acid makes possible the selective isomerization of the double-bond geometry by decreasing the rate of the competing protodesilylation.On the basis of the finding that the isomerization proceeds on the surface of the silica gel activated with benzenesulfinic acid and that benzenesulfinic esters such as ethyl, tributylstannyl, and trimethylsilyl benzenesulfinates are also effective as catalysts for the isomerization, the selective isomerization of vinylsilanes was interpreted in terms of the in situ formation of silyl benzenesulfinate bound to a silanol group of the surface of silica gel.