A study of periselectivity in the thermal cyclisation reactions of diene-conjugated diazo compounds: 1,7-cyclisation as a route to 3H-1,2-diazepines and 1,5-cyclisation leading to new rearrangement reactions of 3H-pyrazoles
作者:Ian R. Robertson、John T. Sharp
DOI:10.1016/s0040-4020(01)82434-0
日期:1984.1
A range of diene-conjugated diazo compounds has been generated by the thermal decomposition of the sodium salts of the tosylhydrazones of 1-acyl-1, 3-dienes. Those of type (21) with a relationship of the diazo group and the γ, δ-double bond having a hydrogen atom at the diene terminus cyclised only by 1,7 ring closure to give 3-1,2-diazepines (23). This mode of cyclisation was inhibited by the presence
通过1-酰基-1,3-二烯的甲苯磺酰基hydr的钠盐的热分解,已经产生了一系列二烯共轭的重氮化合物。具有重氮基团和在二烯末端具有氢原子的γ,δ-双键的关系的类型(21)的那些仅通过1,7闭环而环化,得到3 -1,2-二氮杂((23)。这种环化模式被二烯末端甲基或苯基的存在所抑制,例如(45)。这种类型的化合物通过交替的1,5-环闭合而环化,得到3-烯基-3-吡唑类(46)为主要产品。这些观察结果是基于8π电子1,7-电环化反应的螺旋跃迁状态(54)进行解释的。具有γ,δ双键的二烯共轭的重氮化合物,例如(32)也主要通过1,5-电环化而环化,得到3-烯基-3-吡唑,例如(33)。在大多数情况下,在反应条件下3-吡唑重排烯基和氢迁移以产生1-吡唑,例如(34)和(37)。