A new convenient three-step synthesis of the privileged CNS scaffold 1,2,3,4,10,10a-hexahydropyrazino[1,2-a]indoles has been developed. The method makes use of an intramolecular carbene-mediated C-H insertion in phenylpiperazine-derived tosylhydrazones made from 2-fluorobenzaldehydes. Notably, the piperazine can be replaced with other cyclic nitrogen bases and the methodology is successfully extended to pyrrolidine, piperidine, azepane, morpholine, and homopiperazine.
开发了一种新的便捷三步合成特权中枢神经系统骨架1,2,3,4,10,10a-六氢
吡嗪并[1,2-a]
吲哚的方法。该方法利用了由2-
氟苯醛制得的苯基
哌嗪衍生的托磺酰
肼中发生的分子内碳烯介导的C-H插入。值得注意的是,
哌嗪可以被其他环状氮碱替代,该方法成功扩展到了
吡咯烷、
哌啶、七元环胺、吗啉和同
哌嗪。