C-H Activation Reactions Promoted by Iridium and Palladium

Organic Chemistry Seminar Series

In recent years, the activation of C-H bonds has been transformed from an undesired step that deactivates a catalyst, to one that is synthetically useful.  Many of these transformations involve the functionalization of arenes or allylic systems via their C-H bonds.  We have developed several C-H activation reactions, but this talk will focus on the intermolecular allylic oxidation of vinylsilanes using low catalyst loadings of Pd(OAc)₂ to produce the corresponding allylic acetates.  Interestingly, trans-vinylsilanes are unreactive, whereas allylic oxidation reactions of cis-vinylsilanes proceed in good yields giving a single diastereo- and regioisomer of the branched allylic acetate trans-vinylsilane when benzoquinone (BQ) is employed. The use of PhI(OAc)₂ as oxidant in place of BQ provides the branched, cis-vinylsilane as the major product.  Intramolecular allylic etherifications of cis-vinylsilanes that give the corresponding vinyl tetrahydrofurans and –pyrans will also be presented.  Our current efforts toward a mild, regioselective dehydrogenation of unactivated alkanes to alkenes using novel iridium complexes will also be discussed. 

For more information contact Prof. Stefan France (404-385-1796).