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Asymmetric Reduction of Ketones by Phosphoric Acid Derived Catalysts


  • We thank the National Institutes of Health (NIH GM-082935) and the National Science Foundation CAREER program (NSF-0847108) for financial support. We also thank the referees very valuable suggustions.


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A new path to chiral alcohols: Asymmetric reduction of ketones was achieved utilizing a chiral Brønsted acid as precatalyst for the first time. Using catecholborane as the reducing agent, a highly enantioselective formation of chiral secondary alcohols was found with a broad substrate scope. Mechanistic studies indicate that phosphoryl catechol borate derived from the reaction of the Brønsted acid with catecholborane produced the active catalyst (see scheme).