Synthesis of β-cyanoalanine and enantiomerically enriched aspartate derivatives via the Zn- or In-mediated nucleophilic addition to α-imino esters
作者:Arya Jayadev Sudha、Nayyar Ahmad Aslam、Akshey Sandhu、Makoto Yasuda、Akio Baba、Srinivasarao Arulananda Babu
DOI:10.1016/j.tet.2020.131217
日期:2020.6
4-bromocrotonates to enantiopure N-tert-butanesulfinyl α-imino esters gave the corresponding enantiomerically enriched β-vinyl aspartates 10c-e (aspartic acid derivatives) with high diastereoselectivity (syn isomers). The stereochemistry of the vicinal stereocenters of the compounds 10c-e (major isomers) were assigned based on the X-ray structure of a derivative 11d which was obtained from 10c. To show the
我们报道了β-氰基丙氨酸衍生物和对映体富集的天冬氨酸的合成。锌介导的α-溴乙腈加至α-亚氨基酯中,以令人满意的良好产率获得了各种β-氰基丙氨酸衍生物3a-1和5a-d。所述锌或铟-介导的加入α-溴乙腈或2-溴乙酸乙酯于对映体纯ñ -叔-butanesulfinyl α -亚氨基酯,得到相应的产品3M-P在令人满意的产率和非对映选择性。值得注意的是,铟介导的4-溴巴豆酸烷基酯加成对映体ñ -叔-butanesulfinyl α -亚氨基酯,得到相应的对映体富集的β -乙烯基天冬氨酸10C-E (天冬氨酸衍生物)具有高非对映选择性(顺式异构体)。基于衍生自10c的衍生物11d的X射线结构,确定化合物10c-e(主要异构体)的邻近立体中心的立体化学。为了显示β-氰基丙氨酸和β-乙烯基天冬氨酸衍生物的效用,代表性的β-氰基丙氨酸化合物3a / 3b,对5d和天冬氨酸衍生物10c进行选择的合成转化。