Diastereo- and enantioselective allylic SN′ substitution by phenylacetic esters enolates.
摘要:
The Anti-Michael S(N') substitution of gamma-bromo-alpha,beta-unsaturated esters 1a-c by Li t.butyl phenylacetate enolate is highly diastereoselective. Asymmetric synthesis can be performed (ee greater-than-or-equal-to 95%) using the enantiomerically pure (1'R,2'S) 2-phenyl cyclohexyl ester 1c.
Reaction of phenylacetate enolates with γ- bromo α,β-unsaturated derivatives: diastereo-and enantioselective allylic substitution
摘要:
The reaction of Li t.butyl phenylacetate enolate with gamma-bromo-alpha,beta-unsaturated esters 1a,b is regio-and stereoselective. Asymmetric synthesis can be performed with a chiral ester 1d. With amide 1c, the regio-and stereoselectivity are poor.