Uttam K Tambar
The University of Texas Southwestern Medical Center at Dallas, USA
Uttam K Tambar received his AB degree from Harvard University in 2000 and his PhD from the California Institute of Technology in 2006 with Professor Brian Stoltz. After he completed his NIH Post-doctoral Fellowship at Columbia University with Professor James Leighton in 2009, he began his independent research career at UT Southwestern Medical Center in Dallas. He is currently an Associate Professor in the Biochemistry Department, a W W Caruth, Jr. Scholar in Biomedical Research, and a Sloan Research Fellowship. He is interested in asymmetric catalysis, natural product synthesis and medicinal chemistry
We have been exploring the selective functionalization of unactivated hydrocarbons. We have developed a catalytic enantioselective allylic amination of unactivated olefins via a [2,3]-rearrangement (Scheme 1). In this method, a diimido-sulfur reagent serves as the source of nitrogen, and it reacts selectively with terminal olefins through a hetero-ene reaction. The resulting zwitterionic ene adduct undergoes a Pd-catalyzed enantioselective [2,3]-rearrangement to generate chiral amines in high enantiomeric excess. Our approach is conceptually distinct from other enantioselective allylic amination strategies. The synthetic utility of our process is being explored by converting simple and inexpensive terminal olefins into functional materials, such as the pharmaceutical drugs Vigabatrin and Januvia. Based on this chemistry, we have also developed a copper-catalyzed allylic alkylation of unactivated olefins and dienes (Schemes 2 and 3). This represents a general method for functionalizing unactivated hydrocarbons with aromatic, aliphatic, and vinyl Grignard reagents. Our recent discoveries represent a conceptual framework for the generalized functionalization of unactivated olefins.