Stereospecific, Ligand-Free Synthesis of All-Carbon Quaternary Stereocenters from Tertiary Benzylic Carboxylates

Nickel-catalyzed, stereospecific cross-couplings via activation of secondary C–O bonds has been well developed in the past few years. Meanwhile, stereospecific cross-couplings of tertiary electrophiles have been rarely explored. Herein, we describe a nickel-catalyzed, ligand-free Suzuki-Miyaura vinylation, using easily prepared, highly enantioenriched tertiary benzylic carboxylates to install all-carbon quaternary stereocenters in high yields and ee’s. In addition to allowing stereospecific vinylation of these substrates for the first time, this method overcomes the longstanding requirement for a naphthyl group on the benzylic carboxylate