Abstract
In recent years, the speaker and his research group have developed a family of highly enantioselective allylboron reagents via hydroboration reactions of allenes with chiral organoboranes. For example, the double allylborating agents A, B, and C were developed via hydroboration reactions of substituted allenylboron intermediates for use in the highly enantio- and diastereoselective synthesis of 1,5-diols via the coupling of two different aldehyde units. The utility of these reagents will be discussed in connection with a highly stereocontrolled synthesis of N-acetyl 13-dihydrotetrafibricin methyl ester. As an extension of this methodology, targeting the synthesis of chiral enolborane reagents for use in enantioselective aldol reactions, they have found that the 1,4-hydroboration of morpholine acrylamides constitutes an exceptionally useful method for synthesis of syn aldols with 96-98% e.e. and >20:1 d.r. Additional applications of this new aldol methodology will also be presented.
About the speaker
Prof William Roush received his PhD in Chemistry from Harvard University in 1977. After an additional year as a postdoctoral associate at Harvard, he joined the faculty of the Massachusetts Institute of Technology as an Assistant Professor. He moved to Indiana University in 1987 and was promoted to Professor in 1989 and Distinguished Professor in 1995. Two years later, he went to the University of Michigan in Ann Arbor as the Warner Lambert/Parke Davis Professor of Chemistry. He served as Chair of Chemistry from 2002-2004. In 2004, Prof Roush relocated with his group to the Scripps Research Institute in Florida, where he currently serves as Professor of Chemistry, Executive Director of Medicinal Chemistry and Associate Dean of the Kellogg School of Science and Technology.
Prof Roush's research interests focus on the stereocontrolled synthesis of stereochemically complex natural products, and on the design and development of new reactions and synthetic methods. He is known for his stereochemical studies and synthetic applications of the intramolecular Diels-Alder reaction and his work in the area of asymmetric and acyclic diastereoselective synthesis, specifically the use of tartrate ester modified allylboronates and other allylmetal compounds for the aldol-like construction of propionate-derived systems. He has also made important contributions the synthesis of deoxyglycosides and polyhydroxylated natural products (his total synthesis of olivomycin A is particularly noteworthy), and to the design and synthesis of inhibitors of cysteine proteases targeting important human pathogens (for example, Trypanosoma, Plasmodium, and Entamoeba species). Since moving to Scripps Florida, his program in chemical biology and medicinal chemistry has expanded to include research on the development of inhibitors of kinases, inhibitors of certain epigenetic targets, inhibitors and activators of nuclear receptors, and studies of small molecule-antibody conjugates as potential therapeutic agents.
Prof Roush received numerous awards including the Alan R. Day Award of the Philadelphia Organic Chemist's Club, the American Chemical Society's Arthur C. Cope Scholar Award, Akron Section Award, and Ernest Guenther Award in the Chemistry of Natural Products, etc. In 1998, he received a Merit Award from the US National Institute of General Medical Sciences. He is a Fellow of the American Association for the Advancement of Science and the American Chemical Society.
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