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
Dynamic resolution of N-methyl pseudoephedrine α-bromo esters in nucleophilic substitution 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-bromo esters are allowed to equilibrate to the thermodynamic ratios before the addition of sulfur nucleophile. We have shown that the
在与三苯甲基硫醇的亲核取代反应中,N-甲基伪麻黄碱α-溴代酯的动态拆分已成功用于不对称制备高达97:3 dr的α-巯基羧酸衍生物。当在添加硫亲核试剂之前使α-溴酸酯达到热力学比平衡时,可获得最佳结果。我们已经表明,手性助剂可以通过还原裂解和酸性醇解反应除去,以分别提供β-三苯甲基硫醇15和α-三苯甲基硫醇酯16,而没有可检测的消旋作用。