Synthesis of 1,1-Disubstituted Alkyl Vinyl Sulfides via Rhodium-Catalyzed Alkyne Hydrothiolation: Scope and Limitations

Described herein are the scope and limitations using Tp*Rh(PPh3)2 as a catalyst for alkyne hydrothiolation with alkyl thiols. In general, catalytic hydrothiolation proceeds in high yields and with high regioselectivity for a wide range of alkynes and thiols. A variety of functional groups were well-tolerated, including nitriles, amines, halogens, ethers, esters and silanes, although strongly coordinating groups were found to be incompatible with hydrothiolation. Both sterically encumbered alkynes and thiols were successful in hydrothiolation. Electron rich alkynes react more rapidly than electron deficient alkynes. Overall, this hydrothiolation protocol provides convenient access to a variety of functionalized branched alkyl vinyl sulfides.