Selective Arylation and Vinylation at the Position of Vinylarenes

In intermolecular Heck reactions of styrene and vinylarenes, the aryl and vinyl groups routinely insert at the position. However, selective insertion at the position has been very rare. Herein, we provide a missing piece in the palette of Heck reaction, which gave >20:1 selectivity. The key to our success is a new ferrocene 1,1-bisphosphane (dnpf) that carries 1-naphthyl groups. Our mechanistic studies revealed that the high selectivity is partly attributable to the steric effect of dnpf. The rigid and bulky 1-naphthyl groups of dnpf sterically disfavor insertion.