Preparation oftrans- andcis-2-allyl-6-alkyl(aryl)-1,2,3,6-tetrahydropyridines based on the reductivetrans-2,6-dialkylation of pyridine. Synthesis of (±)-epidihydropinidine and (±)-dihydropinidine
作者:Yu. N. Bubnov、E. V. Klimkina、A. V. Ignatenko
DOI:10.1007/bf02495652
日期:1998.3
A general method for the preparation of unsymmetricaltrans-2-allyl-6-alkyl(aryl)-1,2,3,6-tetrahydropyridines6 based on a combination of 1,2-addition of RLi to pyridine andtrans-6-allylation with triallylborane in the presence of methanol was elaborated. It was shown thattrans-piperideines (6 (R=Alk, Ph) isomerize into the correspondingcis-2-allyl-6-alkyl(phenyl)-3-piperideines14 on heating with triallylborane
基于 RLi 与吡啶的 1,2-加成和三烯丙基硼烷的反式-6-烯丙基化的组合制备不对称反式-2-烯丙基-6-烷基(芳基)-1,2,3,6-四氢吡啶6的一般方法在甲醇的存在下进行了详细说明。结果表明,反式哌啶(6(R = Alk,Ph)在与三烯丙基硼烷一起加热时异构化为相应的顺式-2-烯丙基-6-烷基(苯基)-3-哌啶14,然后用甲醇和氨基硼烷(16)脱硼碱。化合物 6 和 14 的立体化学由二维 NOE 光谱测定。讨论了形成反式胺 6 及其转化为顺式异构体 14 的可能机制。生物碱 (±)-表二氢吡啶(反式 2-甲基-6-丙基哌啶 2a , 70%) 和 (±)-dihydropinidine (cis-2-methyl-6-propylpiperidine1d,