Synthesis of (2,2-Diborylvinyl)arenes by Rhodium-Catalyzed Desulfanylative gem-Diborylation of 2-Arylvinyl Sulfides.

An unexpected gem-diborylation of 2-arylvinyl sulfides with bis(pinacolato)diboron proceeded efficiently with a rhodium catalyst. A wide range of (2,2-diborylvinyl)arenes are easily synthesized by this method using readily available reagents, including the alkenyl sulfides, that are prepared from general materials in one step. Mechanistic studies indicate that the reaction proceeds from either of the stereoisomers in a stepwise manner via borylative C-S bond cleavage and subsequent dehydrogenative borylation.