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.