Pd-Catalyzed Homologation of Arylboronic Acids as a Platform for the Diversity-Oriented Synthesis of Benzylic C-X Bonds

We report a synthetic platform for the formation of benzyl-ic C-X bonds. Benzylboronic acid pinacol (Bpin) esters are useful syn-thetic intermediates but are commercially uncommon, leading to preparations that typically rely upon stoichiometric metalation. Pd-cat-alyzed formal homologation of arylboronic acids provides access to these compounds that, in turn, allow the formation of C-C, C-O, and C-N bonds from Pd-and Cu-mediated cross-coupling or oxidative pro-cesses. This affords a wide variety of benzylic alcohols, diarylmethanes, benzyl amines, and benzyl ethers. Limitations are disclosed, and the utility is further demonstrated by the generation of analogues of me-clizine.