New Examples of 1,6- and 1,7-Hydrogen Transfer Promoted by an α-Silyl Group in Rhodium(I)-Catalyzed Radical Reactions of Acyclic Enediynes

Abstract

A rhodium(I) catalyst triggers cycloaromatization of ω-trialkylsilylated acyclic enediynes to afford benzosilacycloalkane or vinylsilane products via 1,6- and/or 1,7-hydrogen transfer, presumably effected by radical stabilization by an α-silyl moiety and via a seven- and/or eight-membered rhodacycle intermediate. The addition of a catalytic amount of dimethyl maleate is essential to obtain better yields of the products.