Synthesis of bridged azabicyclic compounds using radical translocation reactions of 1-(o-halogenobenzoyl)-2-(prop-2-enyl)- and -(prop-2-ynyl)-piperidines
作者:Masazumi Ikeda、Yasuhiro Kugo、Tatsunori Sato
DOI:10.1039/p19960001819
日期:——
Methyl 1-(o-bromobenzoyl)-2-(prop-2-enyl)piperidine-2-carboxylate 8a, upon treatment with tributyltin hydride in the presence of azoisobutyronitrile in boiling toluene gave regioselectively the 8-azabicyclo[3.2.1]octane 14a (a 5-exo cyclisation product) in quantitative yield as a diastereomeric mixture (66:34). 1-(o-Bromobenzoyl)-2-(prop-2-enyl)piperidine 13 also gave the 8-azabicyclo[3.2.1]octane
1-(邻-溴苯甲酰基)-2-(丙-2-基)哌啶-2-羧酸甲酯8a,在沸腾的甲苯中,在偶氮异丁腈存在下,用氢化三丁基锡处理,区域选择性地生成8-氮杂双环[3.2.1]辛烷以非对映异构体混合物的定量收率得到14a(5- exo环化产物)(66:34)。1-(邻-溴苯甲酰基)-2-(丙-2-烯基)哌啶13还得到了8-氮杂双环[3.2.1]辛烷16(75%,为非对映异构体混合物),以及吡啶基[2,1- α ]异吲哚酮17(10%)和简单还原产物18(5%)。1-(ø -Iodobenzoyl)-2- [3-(三甲硅烷基)丙-2-炔基]哌啶23得到,除了吡啶并[2,1-一个]异吲哚酮25(18%),8-氮杂双环[3.2.1]辛烷24(75%),其被转化为6-氧代衍生物27。为了比较,还研究了氮杂环丁烷同源物31的行为。