Synthesis of 1,2-Dihydroxyindolizidines from 1-(2-Pyridyl)-2-propen-1-ol

1-(2-Pyridyl)-2-propen-1-ol, obtained by vinylation of commercially available picolinaldehyde, resulted a good starting material for the synthesis of the indolizidine skeleton. In particular, a simple process involving bromination, reduction, and nucleophilic substitution (via elimination and addition) allowed an easy conversion of the starting material into (±)-lentiginosine in ∼27% overall yield.1-(2-吡啶基)-2-丙烯-1-醇（1-(2-Pyridyl)-2-propen-1-ol）由商业化易得的吡啶甲醛（picolinaldehyde）经乙烯基化反应制得，是合成吲哚里西啶骨架（indolizidine skeleton）的优良起始原料。具体而言，通过包含溴化反应、还原反应及亲核取代反应（经消除与加成过程）的简易合成流程，可将该起始原料便捷地转化为(±)-扁豆碱（(±)-lentiginosine），总产率约为27%。