Regio- and Stereoselective Transition Metal-Catalyzed Hydrometallation of SF 5 -alkynes with Group 14 Metalloids (Si, Ge, Sn)

Hydrometallation of polarized alkynes is a powerful technique to access regio- and stereocontrolled vinyl-metal intermediates. The pentafluorosulfanyl (SF 5 ) group, often called "super-CF 3 ", offers a promising, non-PFAS alternative to CF 3 chemistry, combining enhanced electron-withdrawing properties with remarkable stability. While hydrofunctionalization of SF 5 -alkynes has so far been limited to the β-carbon, we report the first regioselective hydrometallation at the α-carbon of SF 5 -alkynes. Palladium- and platinum-catalyzed hydrosilylation, hydrostannylation, and hydrogermylation with Group 14 metalloids delivered α-vinylsilanes, α-vinylstannanes, and α-vinylgermanes in moderate to excellent yields with high regio- and stereoselectivity, outperforming CF 3 -alkynes, whose weaker polarization accounts for their lower selectivity.