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
Carbene-Catalyzed Dynamic Kinetic Resolution of Carboxylic Esters
作者:Xingkuan Chen、Jacqueline Zi Mei Fong、Jianfeng Xu、Chengli Mou、Yunpeng Lu、Song Yang、Bao-An Song、Yonggui Robin Chi
DOI:10.1021/jacs.6b00406
日期:2016.6.15
Carbene-catalyzed reaction of carboxylicesters has the potential to offer effective synthetic solutions that cannot be readily achieved by using the more conventional aldehyde-type substrates. Here we report the first carbene-catalyzed dynamic kinetic resolution of α,α-disubstituted carboxylicesters with up to 99:1 er and 99% yield. The present study clearly illustrates the unique power of carbene-catalyzed