Synthesis of 1,1-disubstituted olefins via catalytic alkyne hydrothiolation/Kumada cross-coupling.

Using recently developed methodology for the regioselective formation of branched alkyl vinyl sulfides, we report a convenient route to 1,1-disubstituted olefins. We demonstrate that n-propanethiol successfully undergoes catalytic alkyne hydrothiolation with both aryl and aliphatic alkynes using Tp*Rh(PPh3)2 as the catalyst. The resulting vinyl sulfides undergo Kumada cross-coupling to afford the desired disubstituted alkene. Both two-step and one-pot procedures are reported.