Rhodium-catalyzed regioselective addition of thioacids to terminal allenes: enantioselective access to branched allylic thioesters.

Rhodium-catalyzed regio- and enantioselective hydrothiolation of terminal allenes with thioacids is reported for the atom-economic synthesis of chiral branched allylic thioesters. By using a rhodium(I) catalyst system, diversities of terminal allenes and thioacids afforded the corresponding branched thioesters in excellent regioselectivity, high yield, and good enantioselectivity. This method was also explored for Fmoc-protected aminothioacids for diastereoselective synthesis of the corresponding thioesters.