Nickel-Catalyzed Regioselective Markovnikov Hydrosilylation of Vinylarenes via Hydrogen Atom Transfer

The nickel-catalyzed highly Markovnikov-type selective hydrosilylation of terminal vinylarenes via a hydrogen atom transfer (HAT) pathway represents an efficient and selective strategy for the synthesis of organosilicon compounds. This method enables the <i>anti</i>-Markovnikov addition of hydrosilanes to vinylarenes to be overcome, favoring the formation of branched silanes with good yield (up to 90% yield) and high regioselectivity (b/l up to 97:3). NiBr₂ and dppp produce a dramatic increase in the yield of α-selective hydrosilylation products. Addition of CuCl can inhibit the byproducts of alkene dimerization very well. The key hydrogen atom transfer step facilitates the generation of benzyl radical intermediates, allowing for mild reaction conditions and broad functional group compatibility.