Stereoselective Route towards 2,5-Disubstituted Piperidine Alkaloids. Synthesis of (+)-Pseudoconhydrine and (±)-epi-Pseudoconhydrine
作者:Joakim Löfstedt、Helena Pettersson-Fasth、Jan-E Bäckvall
DOI:10.1016/s0040-4020(99)01105-9
日期:2000.4
This paper describes a new general approach towards functionalized piperidine alkaloids, based on the stereo- and regioselective palladium(0)-catalyzed nucleophilic ring-opening of vinyl epoxides by nitrogen nucleophiles. The latter reaction provides access to stereodefined anti and syn aminoalcohol derivatives, 1-benzyloxy-5-(p-toluenesulfonamido)-3-alken-2-ols (5), which were transformed to (+)-pseudoconhydrine
本文介绍了一种新的通用方法,以功能化的哌啶生物碱为基础,该方法基于立体和区域选择性钯(0)催化的氮亲核试剂对乙烯基环氧化合物的亲核开环。后者反应提供了访问stereodefined抗和顺式氨基醇衍生物,1-苄氧基-5-(p -toluenesulfonamido)-3-链烯-2-醇(5),将其转化为(+) - pseudoconhydrine(3)和(通过保护(甲硅烷基醚),加氢,脱苄基和环化分别形成±)-表-伪conconhydrine(9)。脱甲苯磺酰化-脱保护得到的终产物具有良好的收率和高的立体异构纯度。