Huw M. L. Davies
  Department of Chemistry
  University of Buffalo

Department Lecture Series
Thursday October 18, 9:45 am, Smith 331

C-H Activation: Applications in Organic Synthesis

Abstract: Recent studies have shown that rhodium-stabilized carbenoids, substituted with both a donor and an acceptor group, are capable of a range of new and highly selective transformations. A particularly attractive transformation is the intermolecular C-H activation, involving rhodium carbenoid induced C-H insertion. Dirhodium tetraprolinates are exceptional chiral catalysts for this type of chemistry and virtually all of the C-H activation reactions proceed with high enantioselectivity (80-95% ee). An effective C-H activation process offers new disconnection strategies for synthesis. Examples will be given on how the chemistry can be considered to be equivalent to some of the classic reactions of organic synthesis, such as the aldol reaction, the Mannich reaction, the Claisen rearrangement and the Michael addition.
The second part of the presentation will describe a very unusual transformation, the "combined C-H activation/Cope rearrangement." The most notable feature of this transformation is its extremely high stereoselectivity, often occurring in >98% de and 99% ee. The synthetic potential of this process will be illustrated by a very direct synthesis of the marine natural products in which all three stereocenters are controlled in the key combined C-H activation/Cope rearrangement step.