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.
Kang, Kyoung Hee; Heo, Ji Hyeon; Kim, Yongtae, Heterocycles, 2007, vol. 71, # 5, p. 1163 - 1171
作者:Kang, Kyoung Hee、Heo, Ji Hyeon、Kim, Yongtae、Park, Yong Sun
DOI:——
日期:——
Dynamic Resolution of α-Bromo-α-Alkyl Esters Using N-Methyl Pseudo-ephedrine as a Chiral Auxiliary: Asymmetric Syntheses of α-Amino Acid Derivatives
作者:Sang-kuk Lee、Jiyoun Nam、Yong Sun Park
DOI:10.1055/s-2002-25373
日期:——
esters 1, 4 and 5 are allowed to equilibrate before the addition of nucleophile. This simple epimerization-substitution sequence provides a practical protocol for asymmetric syntheses of α-amino acidderivatives 2, 7 and 8 up to 98:2 enantiomeric ratio.
Dynamic thermodynamic resolution of N-methylpseudoephedrine α-bromo esters for asymmetric syntheses of α-hydroxy carboxylic acid derivatives
作者:Jiyoun Nam、Sang-kuk Lee、Yong Sun Park
DOI:10.1016/s0040-4020(03)00285-0
日期:2003.3
esters with an oxygen nucleophile is described. Temperature controlled epimerization–substitution sequence provides a practical protocol for the preparation of highly enantioenriched α-hydroxy carboxylic acidderivatives up to 72% yield with 99:1 er.