Our research program is focused on the development of conceptually new catalytic methods for organic synthesis. Our goals are to uncover, study, and design new catalytic cycles as well as develop reactions of practical value. We achieve these goals through a mixture of organometallic mechanistic studies, organic reaction development, and collaborations. Our researchers come from both synthetic organic and inorganic backgrounds and all students can expect to become well versed in current organic methods and organometallic mechanisms. At present, we are particularly inspired by the diverse reactivity of first-row transition metals (Mn, Fe, Co, Ni, Cu), the untapped potential of combining organic radicals with transition metals, multimetallic catalysis, semiconductor nanoparticles, and the challenge of cross-coupling two different electrophiles selectively.
A variety of cross-electrophile coupling reactions that have been developed in the Weix group, including aryl halides with alkyl halides, alkyl halides with acid chlorides, enones with organic halides, allylic acetates with organic halides, and epoxides with aryl halides (Figure 1). A particular strength of cross-electrophile coupling is functional group compatibility and these reactions are increasingly being used by researchers in both academia and industry.
Our mechanistic studies have uncovered three general approaches to selective cross-coupling: the coupling of an organic radical with an organometal intermediate (Figure 2), the selective generation of allylnickel intermediates from enones that can then react with other electrophiles (Figure 3), and the selective cross-coupling of similar electrophiles through the cooperative action of palladium and nickel (mechanism still under investigation). These mechanistic studies have, in turn, led to the development of new reactions, both in our group and in other groups. For example, the revelation that the coupling of alkyl halides with aryl halides proceeds by the coupling of an aryl halide with an alkyl radical led to the development of alternative methods for generating radicals, such as with Ti(III) and Co(Pc).
We have also recently begun to examine the potential of semiconductor quantum dots (QDs) as photoredox catalysts in organic synthesis in collaboration with Prof. Todd Krauss (Univ. of Rochester). While QDs have proven to be impressive materials for imaging and solar energy conversion, they have not been applied to complex organic reactions. We have shown that even well-known CdSe QDs are impressive catalysts for a variety of known photoredox reactions (Figure 4), achieving remarkably low catalyst loadings and promising scope. We are currently exploring new, tailored materials and developing new chemistry that takes advantage of the unique properties of these nanoscale catalysts.
For further information, see our articles on the Publications page and, for the latest, our Group News Twitter feed!