Kim Jinsoo, Bruning John, Park Kevin E, Lee David J, Singaram Bakthan
Department of Chemistry and Biochemistry, University of California Santa Cruz, 1156 High Street, Santa Cruz, California 95064, USA.
Org Lett. 2009 Oct 1;11(19):4358-61. doi: 10.1021/ol901677b.
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.
报道了使用TarB-NO(2)和硼氢化钠对α,β-不饱和酮进行不对称1,2-还原反应。简单的环烯酮生成的产物对映体过量值较低。然而，带有α-取代基（如卤化物、烷基和芳基）的环烯酮通过该体系可进行对映选择性还原，以高达99%的对映体过量值生成手性烯丙醇。TarB-NO(2)的起始原料价格低廉，并且通过简单的酸萃取就能轻松地以高产率回收硼酸。
