A Two-Step Synthesis of 3,4-Disubstituted Piperidines from Acyclic Precursors through Tetrahydropyridine Intermediates
作者:José Aurrecoechea、José Gorgojo、Carlos Saornil
DOI:10.1055/s-0029-1218599
日期:2010.2
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。