University of Nebraska-Lincoln
807B Hamilton Hall
Lincoln, NE 68588-0304
We are using chirality-directed metal complexation to define an exciting new strategy for preparing chiral self-assembled ligand (SAL) libraries. Using SALs to prepare heterobimetallic catalyst systems is an effective way to carry out catalytic asymmetric synthesis such as the palladium-catalyzed asymmetric allylic amination reaction illustrated. Screening a library of 50 SALs led to the discovery of an optimal ligand scaffold for this reaction. Asymmetric catalysis will no doubt define the future of modern synthetic organic chemistry and a variety of new reactions and catalyst systems are under investigation.
Few scientific endeavors can compare to the challenge of complex molecule total synthesis. Metal-catalyzed reactions under development in my group are being used as pivotal strategies for the asymmetric total syntheses of a variety of biologically active structures, including for example, prostaglandin and isoprostanes, the polyether antibiotic A80577, and as illustrated, dolabellane diterpenes and indolizidine alkaloids. Here again, combichem strategies for reaction optimization play a key role in our studies.
Several projects collaborate with groups in other disciplines to provide diverse synthetic opportunities on interdisciplinary research problems. The design and synthesis of antimicrobial drugs target a novel class of microbial enzymes, a project carried out in collaboration with groups in the biochemistry department and animal science departments. Other collaborative projects directed toward enzyme inhibition and drug design involve the design and synthesis of chemical libraries. A collaboration with a research group in the physics and materials science department works to improve the performance of piezoelectric and related devices fabricated from designed polymers using nanoscale material structuring.
(1) Two-Stage Optimization of a Supramolecular Catalyst for Catalytic Asymmetric Hydroboration. Shin A. Moteki, Kazuya Toyama, Zeyu Liu, Jing Ma, Andrea Holmes, James M. Takacs*. Chem commun. 2012, 48, 263-265
(2) Catalytic Asymmetric Hydroboration of β,γ-Unsaturated Weinreb Amides: Surprising Influence of the Borane, Smith, Sean M.; Takacs, James M. Chem Comm, 2011, 47, 7812-7814
(3) Remarkable Levels of Enantioswitching in Catalytic Asymmetric Hydroboration Smith, Sean M.; Takacs, James M. Organic Letters, 2010, 2010, 12 (20), pp 4612–4615