1. Alkylidene Complexes; Synthesis and Mechanisms
This research involves the synthesis of new high oxidation state early metal complexes that contain an alkylidene ligand. Since 2007 the majority of investigations involve new monoalkoxide pyrrolide (MAP) complexes in which the metal is a stereogenic center. MAP catalysts offer many practical advantages over previous bisalkoxide or diolate catalysts, and also allow several fundamental mechanistic issues to be addressed for the first time. Monoalkoxide halide (MAX) complexes have opened a new chapter in metathesis chemistry of difficult substrates, especially electron poor olefins such a dihaloethylenes. The most recent results of fundamental interest concern disubstituted alkylidene complexes and the mechanism of formation of alkylidene complexes from olefins. Recent papers relevant to this area include publications 608, 610, 611, 613, 614, and 616.
2. Olefin Metathesis in Organic Chemistry
This research involves the application of metathesis reactions in organic chemistry in collaboration with A. H. Hoveyda. Most recently the research has focussed on reactions that produce as high as >99% Z products in good yields. Examples include Z-selective coupling of terminal olefins, ethenolysis, cross-metathesis, ring-closing, or alkane metathesis reactions. Applications are focussed on the synthesis of natural products. A recent advance has been the stereoselective (Z) cross metathesis of ordinary olefins with electron poor olefins such as Z 1,2-dichloroethylene or Z-1,1,1,4,4,4-hexafluoroethylene. Recent papers relevant to this area include publications 586, 588, 595, 602, and 604.
3. Surface Organometallic Chemistry
This research is a collaboration with C. Copéret at the ETH on applications of the most recent homogeneous olefin metathesis results toward the synthesis of analogous silica-supported catalysts. Recent papers relevant to this area include publications 605 and 612.