title: Highly enantioselective and regioselective carbonyl reduction of cyclic alpha,beta-unsaturated ketones using TarB-NO2 and sodium borohydride.
abstract: Asymmetric 1,2-reduction of alpha,beta-unsaturated ketones using TarB-NO(2) and NaBH(4) is reported. Simple cycloalkenones give products in low enantiomeric excess. However, cycloalkenones with alpha-substituents, such as halides, alkyl, and aryl, have been enantioselectively reduced with this system to yield chiral allylic alcohols in enantiomeric excess up to 99%. The starting materials for TarB-NO(2) are inexpensive, and the boronic acid can be easily recovered in high yield by a simple acid extraction.
authors.affiliation: Department of Chemistry and Biochemistry, University of California Santa Cruz, 1156 High Street, Santa Cruz, California 95064, USA.
authors.forename: Jinsoo
authors.initials: J
authors.lastname: Kim
authors.forename: John
authors.initials: J
authors.lastname: Bruning
authors.forename: Kevin E
authors.initials: KE
authors.lastname: Park
authors.forename: David J
authors.initials: DJ
authors.lastname: Lee
authors.forename: Bakthan
authors.initials: B
authors.lastname: Singaram
mesh_terms: D001894:Borohydrides / Q000737:chemistry*; D001897:Boronic Acids / Q000737:chemistry*; D004952:Esters / Q000737:chemistry*; D007659:Ketones / Q000737:chemistry*; D008968:Molecular Conformation; D010084:Oxidation-Reduction; D020005:Propanols / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D001894:Borohydrides; D001897:Boronic Acids; D004952:Esters; D007659:Ketones; D020005:Propanols; C006463:allyl alcohol; C025364:sodium borohydride