Cyclocondensation between acyclic 5-aminopent-2-enoate esters and aliphatic aldehydes containing an unsubstituted α-methylene unit affords 1,2,3,4-tetrahydropyridine derivatives in good yields. The reaction has been applied to a range of aldehydes, showing good functional group tolerance. Chemoselective hydride reduction of the enamine double bond provides 3,4-disubstituted tertiary piperidine derivatives with acceptable to good diastereoselectivities, whereas catalytic hydrogenation of N-benzyl derivatives leads directly to the corresponding secondary piperidines.
无环
5-氨基戊-2-烯酸酯和含有未取代的 α-亚甲基单元的脂肪醛之间的环缩合以良好的产率提供 1,2,3,4-四氢
吡啶衍生物。该反应已应用于一系列醛,显示出良好的官能团耐受性。烯胺双键的
化学选择性
氢化物还原提供了具有可接受的良好非对映选择性的3,4-二取代的叔
哌啶衍
生物,而N-苄基衍
生物的催化氢化直接产生相应的仲
哌啶。