Organic Chemistry

Enantioselective Transition-Metal Catalysis via Anion Binding with Chiral Hydrogen-Bond Donors



Asymmetric transition-metal catalysis represents a powerful strategy for accessing enantiomerically enriched molecules. Here, we report a new approach for inducing enantioselectivity in transition-metal-catalyzed reactions that relies on neutral hydrogen-bond donors (HBDs) that bind anions of transition-metal complexes to achieve enantiocontrol and rate enhancement through ion pairing in concert with other noncovalent interactions. A cooperative anion-binding effect of a chiral bis-thiourea HBD is demonstrated to lead to high enantioselectivity (up to 99% enantiomeric excess) in intramolecular ruthenium-catalyzed propargylic substitution reactions. Experimental and computational mechanistic studies reveal the attractive interactions between electron-deficient arene components of the HBD and the metal complex that underlie enantioinduction and the acceleration effect.


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Supplementary material

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Supporting Information
Full experimental protocols, characterization data, optimization data, kinetics data, Job plot, ROESY data, computational analysis