Asymmetric syntheses of α-mercapto carboxylic acid derivatives by dynamic resolution of N-methyl pseudoephedrine α-bromo esters
作者:Jiyoun Nam、Sang-kuk Lee、Kee Yong Kim、Yong Sun Park
DOI:10.1016/s0040-4039(02)02020-8
日期:2002.11
Dynamicresolution of N-methyl pseudoephedrine α-bromoesters in nucleophilicsubstitution reaction with trityl thiol has been successfully used for the asymmetric preparation of α-mercapto carboxylic acid derivatives up to 97:3 dr. The best results are obtained when α-bromoesters are allowed to equilibrate to the thermodynamic ratios before the addition of sulfur nucleophile. We have shown that the
Dynamic resolution of α-halo chiral esters for the synthesis of 3-substituted piperazin-2-ones
作者:Jung In Jang、Seock Yong Kang、Kyoung Hee Kang、Yong Sun Park
DOI:10.1016/j.tet.2011.06.055
日期:2011.8
Dynamicresolution of α-halo esters derived from five chiral alcohols has been investigated in nucleophilicsubstitution with ethylenediamine nucleophiles. Stereoselective substitution of α-halo esters and following spontaneous cyclization provide a practical protocol for asymmetricsyntheses of 3-substituted piperazin-2-ones up to 94:6 er.