The development of new methods that result in the formation of carbon-hetero bonds is synthetically challenging. Current technologies to access these important bonds rely on extensive functional group manipulation or employ sensitive transition metal complexes. A powerful solution to address these limitations would be the development of selective C-H methylene activation by cationic platinum(ll) complexes. The ability to directly transform a C-H bond into a carbon-heteroatom bond would dramatically alter current perceptions about bond formation. The mild reaction conditions of the Shilov oxidation are a significant advantage for the use of cationic platinum(ll) complexes. An approach that utilizes cationic Pt(ll) complexes for the regio- and enantioselective functionalization of benzylic methylene C-H bonds is outlined within this proposal. Reaction conditions and Iigands that facilitate regioselective methylene C-H activation will be identified through mechanistic experiments designed to evaluate stereoselectivity. After regioselective benzylic C-H activation is realized, formation of carbon-heteroatom and carbon-carbon bonds from well-defined platinum organometallic complexes will be attempted. The reaction will be made catalytic in platinum through the use of stoichiometric copper. When appropriate chiral, non-racemic ligands are employed, this sequence should be capable of asymmetric catalysis. Ultimately, this method is envisioned to allow direct asymmetric transformation of benzy!ic methylene C-H bonds into carbon-hetero or C-C bonds. ? ?
