Iridium-Catalyzed Borylation of Secondary Benzylic C–H Bonds Directed by a Hydrosilane
journal contributionposted on 05.06.2013, 00:00 by Seung Hwan Cho, John F. Hartwig
Most functionalizations of C–H bonds by main-group reagents occur at aryl or methyl groups. We describe a highly regioselective borylation of secondary benzylic C–H bonds catalyzed by an iridium precursor and 3,4,7,8-tetramethyl-1,10-phenanthroline as the ligand. The reaction is directed to the benzylic position by a hydrosilyl substituent. This hydrosilyl directing group is readily deprotected or transformed to other functional groups after the borylation reaction, providing access to a diverse set of secondary benzylboronate esters by C–H borylation chemistry.