N??Heterocyclic Carbene??Mediated Enantioselective Addition of Phenols to Unsymmetrical Alkylarylketenes

C Concellon, N Duguet…

Index: Concellon, Carmen; Duguet, Nicolas; Smith, Andrew D. Advanced Synthesis and Catalysis, 2009 , vol. 351, # 17 p. 3001 - 3009

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Citation Number: 62

Abstract

Abstract Chiral N-heterocyclic carbenes (NHCs) mediate the enantioselective addition of 2- phenylphenol to unsymmetrical alkylarylketenes, 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 from pyroglutamic ...