Current Research

Palladium Catalyzed Alkene Difunctionalization Reactions

A principal goal of our research program is the development of new Pd-catalyzed reactions that transform readily accessible substrates into complex molecules. Much of our efforts in this vein have been directed towards a new reaction for the stereoselective conversion of alkenes bearing pendant nucleophiles, such as amines, or alcohols, into heterocyclic products such as pyrrolidines or tetrahydrofurans. These transformations effect formation of both a carbon-carbon and a carbon-heteroatom bond and up to two stereocenters in a single step. We are currently exploring the scope and limitations of these transformations (eq 1), the mechanism of these processes (eq 2), and the extension of this methodology to the synthesis of other interesting heterocycles. In addition, we are also pursuing catalytic enantioselective variants of these transformations (eq 3).

Enantioselective Construction of Functionalized Quaternary Carbon Stereocenters

Many interesting biologically active natural products contain tertiary alcohol stereocenters. We have recently developed a new approach to the construction of these moieties via tandem asymmetric Wittig rearrangement/Aldol reactions and Wittig rearrangement/Mannich reactions. These transformations afford 1,2-diols and 1,2-amino alcohols bearing quaternary stereocenters with high diastereoselectivity and enantioselectivity. We are currently examining the use of this method for the generation of other types of functionalized quaternary carbon stereocenters.

Asymmetric Total Synthesis of Natural Products

We are currently exploring the application of the methods described above to the construction of several different natural products. Molecules of past, present, and future interest are illustrated above.