N-Heterocyclic Carbene-Mediated Enantioselective Addition of Phenols to Unsymmetrical Alkylarylketenes
作者:Carmen Concellón、Nicolas Duguet、Andrewâ D. Smith
DOI:10.1002/adsc.200900538
日期:2009.11
Chiral N-heterocyclic carbenes (NHCs) mediate the enantioselectiveaddition of 2-phenylphenol to unsymmetricalalkylarylketenes, delivering α-alkyl-α-arylacetic acid derivatives with good levels of enantiocontrol (up to 84% ee). Enantiodivergent stereochemical outcomes are observed using 2-phenylphenol and benzhydrol in the NHC-promoted esterification reaction using a triazolium precatalyst derived