Cobalt-catalyzed chelation-assisted C-C bond formation via C-H bond activation.
Date of Issue2013
School of Physical and Mathematical Sciences
During the past decades, transition metal-catalyzed chelation-assisted C–H bond functionalization has been developed as an efficient and regioselective synthetic strategy. While this chemistry has met with significant success with expensive second-row transition metals, catalysis with cheaper first-row transition metals could lead to the development of cost-effective alternative catalysts as well as the discovery of new reactions. This thesis describes the development of cobalt-based catalysts for chelation-assisted C–H bond functionalization reactions. A serials of C–C bond forming reactions, including alkenylation, alkylation, and arylation, have been achieved on aromatic substrates bearing pyridine or imine directing groups. The cobalt catalysts not only serve as mild and less expensive alternatives to noble metal catalysts for existing reactions, but also show unique reactivities and selectivities and thus enable transformations that were previously difficult to achieve.