Thioether-directed platinum-catalyzed hydrosilylation of olefins

Homoallylic thioethers facilitate the platinum-catalyzed hydrosilylation of olefins with phenyldimethylsilane. As a control, thioether substrates are shown to hydrosilylate at room temperature under conditions where no hydrosilylation is observed for isosteric substrates that lacked thioether groups. Modest diastereoselection is observed, between 2 and 5 to 1. Hydrogenation is a competing reaction that becomes prominent for internal olefins. The internal diene 6a undergoes regioselective 1,2-hydrogenation of the double bond proximal to the homoallyl thioether moiety.