Lewis Base Activation of Grignard Reagents with <i>N</i>-Heterocyclic Carbenes. Cu-Free Catalytic Enantioselective Additions to γ-Chloro-α,β-Unsaturated Esters
作者:Yunmi Lee、Amir H. Hoveyda
DOI:10.1021/ja067456m
日期:2006.12.1
activation of alkylmagnesium halides with a chiral bidentate N-hetrocyclic carbene (NHC), formed in situ from the imidazolinium chloride precursor, is reported. The Cu-free catalytic asymmetric allylic alkylation (AAA) of alpha-alkyl-gamma-chloro-alpha,beta-unsaturated esters with alkyl-based Grignard reagents is promoted in the presence of 5-10 mol % of the chiral imidazolinium salt to afford synthetically