Natural Product Synthesis, Organometallic Chemistry, Homogeneous Catalysis
Office: Room 315 Chemistry and Biochemistry Building
Lab: Rooms 306 and 308 Chemistry and Biochemistry Building
P.O. Box 173400
Bozeman, MT 59717
Ph: 406 994 5408
Fax: 406 994 5407
B.S., University of California, Los Angeles, 1976; M.S., University of California, Los Angeles, 1977; Ph.D., Rice University, 1980; Postdoctoral, Stanford University, 1981.
· CHMY 554 ORGANOMETALLIC CHEMISTRY
Awards and Professional Activities:
Departmental Scholar (Chemistry), 1974 - 1976 University of California, Los Angeles, CA; Rice Graduate Fellowship (Chemistry), 1976 - 1977, Rice University, Houston, TX; NIH Postdoctoral Fellow (Chemistry), 1979 - 1980, Stanford University, Stanford, CA; Alfred P. Sloan Fellow, 1989 - 1991; Alexander von Humboldt Fellow, 1993 - 1995; Wiley Research Award, 1994; Cox Award for Scholarship and Creative Activity, 1996; Montana State University Award for Excellence in Teaching, 1996; Japan Society for the Promotion of Science Fellow, 1997.
Livinghouse Group Overview
The primary focus of Professor Livinghouse\'s research involves the discovery of new carbon-carbon and carbon-heteroatom bond forming reactions with particular emphasis on the application of these to the synthesis of biologically active compounds. The aforementioned goals are being pursued on three major experimental fronts. A summary of these appears below.
New Sequences for the Initiation of Cationic Cascade Annulations
In 1987 the Livinghouse group disclosed that representative polyene cyclizations could be selectively initiated by novel sulfenium ion equivalents. The significance of this finding derives from the unique ability of these cyclizations to convert acyclic precursors to polycyclic products with the net incorporation of new functionalities (e.g., arylthio groups). The application of this new method to the appropriate substrates has led to syntheses for the diosphenol diterpenes(Ã‚Â±)-totarolone and (Ã‚Â±)-totarol as well as (Ã‚Â±)-nimbidiol (Tetrahedron Lett.,30, 1499, 1989). This method has also been successfully applied to the synthesis of the antitumor agent taxodione (J. Chem. Soc. Chem. Commun.,502, 1992; Tetrahedron, 50, 9229, 1994) in addition to a forscolin model.
Organic Synthesis Using Low Valent Complexes of Early Transition Metals
Within the last several years, the Livinghouse group has become heavily engaged in the development and application of synthetic methods involving low valent group IV and group V metals. The first synthetically practical zirconocene equivalent was discovered in our laboratory. This reagent, [(Cp)2Zr(DMAP)2], possesses sequentially displaceable dimethylaminopyridine ligands which permit its use in intermolecular two component coupling reactions involving unsymmetri-cal partners (Tetrahedron Lett.,30, 3495, 1989). Moreover, this species and related complexes have proven to be exceptionally versatile reagents for promoting enyne macrocyclization reactions (Tetrahedron,50, 4421, 1995) as well as the cocylization of hydrazone moieties with carbon-carbon multiple bonds (J. Am. Chem. Soc.,111, 4495, 1989). In addition, the Livinghouse group has reported the first synthetically practical examples of intramolecular [2+2] cycloadditions involving group IV metal-imido complexes and alkynes (J. Am. Chem. Soc.,114, 5459, 1992). The synthetic viability of this new methodolo-gy was subsequently demonstrated by us in a concise total synthesis of the indolizidine alkaloid (Ã‚Â±)-monomorine (J. Org. Chem.,57, 1323, 1992) and the potent antifungal (+)-preussin (J. Am. Chem. Soc.,115, 11485, 1993). In addition, we have shown that a wide variety of functionally differentiated heterocycles can be synthesized using this methodology (Organometallics,16, 1523, 1997).
Homogeneous Catalysis of Cycloaddition Reactions by Transition Metal Complexes
On going efforts in our laboratories have culminated in the development of novel procedures for effecting the catalysis of representative intramolecular [4+2] and [2+2+2] cycloaddition reactions on Rh(I) templates (J. Am. Chem. Soc.,112, 4965, 1990). Significantly, we have discovered that highly enantioselective variations of these transforma-tions can be achieved by the use of rhodium catalysts modified by specifically designed chiral bisphosphine ligands which differentiate the metal center both spatially and electronically (Tetrahedron,50, 6155, 1994). These new chiral rhodium complexes are currently being exploited in asymmetric variations of the Rh(I) catalyzed [4+2] cycloaddition reaction (Tetrahedron,50, 6145, 1994) and the hydroboration of alkenes. Recently, we have discovered a new protocol for effecting [2 + 2 + 1] cyclopentenone annulations that are catalyzed by cobalt complexes (J. Am. Chem. Soc.,118, 2285, 1996; Tetrahedron Lett.,39, 7637 and 7641, 1998). This remarkable catalytic reaction is currently being exploited in an efficient synthetic approach to the alkaloid magellanenone as well as several other natural products and bioactive molecules.
Chemistry & Biochemistry
103 Chemistry and Biochemistry Building
PO Box 173400
Bozeman, MT 59717