Highly enantioselective and regioselective carbonyl reduction of cyclic alpha,beta-unsaturated ketones using TarB-NO2 and sodium borohydride.
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.
Kim
Jinsoo
J
Department of Chemistry and Biochemistry, University of California Santa Cruz, 1156 High Street, Santa Cruz, California 95064, USA.
Bruning
John
J
Park
Kevin E
KE
Lee
David J
DJ
Singaram
Bakthan
B
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
D001894:Borohydrides; D001897:Boronic Acids; D004952:Esters; D007659:Ketones; D020005:Propanols; C006463:allyl alcohol; C025364:sodium borohydride