Highly Enantioselective Epoxidation of α,β-Unsaturated Ketones Catalyzed by Rare-Earth Amides [(Me<sub>3</sub>Si)<sub>2</sub>N]<sub>3</sub>RE(μ-Cl)Li(THF)<sub>3</sub> with Phenoxy-Functionalized Chiral Prolinols
作者:Chao Zeng、Dan Yuan、Bei Zhao、Yingming Yao
DOI:10.1021/acs.orglett.5b00833
日期:2015.5.1
A simple and efficient catalytic enantioselective epoxidation of alpha,beta-unsaturated ketones has been successfully developed, which was catalyzed by rare-earth metal amides [(Me3Si)(2)N](3)RE(mu-Cl)Li(THF)(3) (RE = Yb (1), La (2), Sm (3), Y (4), Lu (5)) in the presence of phenoxy-functionalized chiral prolinols at room temperature using tert-butylhydroperoxide (TBHP) as the oxidant. The combination of an Yb-based amide 1 and a chiral proligand (S)-2,4-di-tert-butyl-6-((2-(hydroxydiphenylmethyl)pyrrolidin-1-yl)methyl)phenol) performed very well, and both the yields and the enantiomeric excess of the chiral epoxides reached up to 99% and 99% ee.