Highly Selective Hydrothiolation of Unsaturated Organosilicon Compounds Catalyzed by Scandium(III) Triflate

The first use of a Lewis acid catalyst in the addition reaction of both aromatic and aliphatic thiols to unsaturated organosilicon compounds is reported. In catalytic tests, scandium(III) triflate demonstrates high catalytic activity in this process. Under mild conditions (25 °C, room temperature, 1–10 h) a number of thioether‐functionalized organosilicon species are obtained with appreciable selectivity. This study constitutes the first example of allylsilane hydrothiolation that gives the Markovnikov regioisomer as the main product. Ethynylsilanes are also successfully used in the hydrothiolation reaction in the presence of Sc(OTf)₃.