Catalytic borylation of o-xylene and heteroarenes via C-H activation

Iridium and rhodium complexes catalyze the borylation of xylene and different heteroarenes using pinacolborane via C-H activation. Various five-membered heterocycles such as thiophene, pyrrole, thionaphthene, and indole derivatives yield the borylated products in moderate to good yields. In general, the reactions proceed with high selectivity to give borylation ortho to the heteroatom. (C) 2003 Elsevier B.V. All rights reserved.