The aim of this research program is the design and study of soluble transition metal complexes that enantioselectively catalyze synthetically valuable transformations of organic compounds. Asymmetric catalysts can provide the most efficient and practical routes to biologically active optically pure materials, and the need for enantiomerically pure materials calls for highly stereoselective catalysts for a broad range of substrates. This proposal focuses on the development and study of chiral salicylidenaminato (salen)-based epoxidation catalysts. Initial studies have revealed that salen-based systems provide practical access to chiral epoxides from a unfunctionalized olefins with very good to moderate selectivity. Strategies to increase enantioselectivity to very high levels are outlined based on a proposed highly predictive stereochemical model for oxygen atom transfer from metals to olefins. The model will be thoroughly tested using crystallographic and solution phase characterization of catalyst precursors and reactive intermediates. Correlation of substrate and catalyst structure with observed enantioselectivities can then permit valuable insight into the transition structure geometries of oxygen-atom-transfer from metal to olefin. The chiral salen complexes are very accessible through simple high-yield synthetic procedures, and this allows screening of a variety of potential catalysts. Strategies are described for systematic tuning of the steric properties of the salen ligands, including the preparation of sterically hindered salicylaldehyde derivatives and the synthesis of a variety of new C2-symmetric chiral diamines. Catalyst lifetimes will be maximized through variation of ligand and metal, and identification of the decomposition pathways under carefully controlled reaction conditions. The synthetic utility of the existing and newly developed catalysts will be illustrated through reactions on a series of unfunctionalized and highly complex substrates, and through the execution of large scale asymmetric epoxidations that afford valuable chiral products from simple olefins. With proper development, chiral salen based systems will provide previously inaccessible chiral building blocks and end-products of great value to pharmaceutical synthesis. The possible utility of existing and newly developed salen based complexes as asymmetric catalysts in other reactions will also be examined. Targeted applications include chlorohydrin cyclization, sulfide oxidation, and Lewis acid-promoted alkylations and cycloadditions of carbonyl compounds.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM043214-03
Application #
3302201
Study Section
Medicinal Chemistry Study Section (MCHA)
Project Start
1991-01-01
Project End
1993-07-01
Budget Start
1993-01-01
Budget End
1993-07-01
Support Year
3
Fiscal Year
1993
Total Cost
Indirect Cost
Name
University of Illinois Urbana-Champaign
Department
Type
Schools of Arts and Sciences
DUNS #
041544081
City
Champaign
State
IL
Country
United States
Zip Code
61820
Wendlandt, Alison E; Vangal, Prithvi; Jacobsen, Eric N (2018) Quaternary stereocentres via an enantioconvergent catalytic SN1 reaction. Nature 556:447-451
Zhou, Biying; Haj, Moriana K; Jacobsen, Eric N et al. (2018) Mechanism and Origins of Chemo- and Stereoselectivities of Aryl Iodide-Catalyzed Asymmetric Difluorinations of ?-Substituted Styrenes. J Am Chem Soc 140:15206-15218
Kwan, Eugene E; Zeng, Yuwen; Besser, Harrison A et al. (2018) Concerted nucleophilic aromatic substitutions. Nat Chem 10:917-923
Mennie, Katrina M; Banik, Steven M; Reichert, Elaine C et al. (2018) Catalytic Diastereo- and Enantioselective Fluoroamination of Alkenes. J Am Chem Soc 140:4797-4802
Banik, Steven M; Levina, Anna; Hyde, Alan M et al. (2017) Lewis acid enhancement by hydrogen-bond donors for asymmetric catalysis. Science 358:761-764
Klausen, Rebekka S; Kennedy, C Rose; Hyde, Alan M et al. (2017) Chiral Thioureas Promote Enantioselective Pictet-Spengler Cyclization by Stabilizing Every Intermediate and Transition State in the Carboxylic Acid-Catalyzed Reaction. J Am Chem Soc 139:12299-12309
Banik, Steven M; Mennie, Katrina M; Jacobsen, Eric N (2017) Catalytic 1,3-Difunctionalization via Oxidative C-C Bond Activation. J Am Chem Soc 139:9152-9155
Park, Yongho; Harper, Kaid C; Kuhl, Nadine et al. (2017) Macrocyclic bis-thioureas catalyze stereospecific glycosylation reactions. Science 355:162-166
Kwan, Eugene E; Park, Yongho; Besser, Harrison A et al. (2017) Sensitive and Accurate 13C Kinetic Isotope Effect Measurements Enabled by Polarization Transfer. J Am Chem Soc 139:43-46
Park, Yongho; Schindler, Corinna S; Jacobsen, Eric N (2016) Enantioselective Aza-Sakurai Cyclizations: Dual Role of Thiourea as H-Bond Donor and Lewis Base. J Am Chem Soc 138:14848-14851

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