作者:Stephen F. Nelsen、Silas C. Blackstock、Timothy B. Frigo
DOI:10.1016/s0040-4020(01)87595-5
日期:1986.1
protonate the azo compound before adding the diene. Preparations of the neutral hydrazines derived from 2,3-diazabicyclo[2.2.2]oct-2-ene(5) with 1,3-cyclohexadiene(6) and from 2,3-diazabicyclo [2.2.1] hept-2-ene (10) with 6 and 1,3-cycloheptadiene (7,11, and 13, respectively) as well as the saturated hydrazines derived by catalytic hydrogenation (9,12, and 14, ropectively) are reported. The neutral adduct
Diels-Alder将双环偶氮化合物加到环状二烯中会生成双-N,N'-双环肼,但事实证明该反应是吸热的。加合物的碱度高于偶氮化合物,使加成反应的吸热量降低13.6–14.1 kcal mol -1:(在水中)如果使用质子化的偶氮化合物代替中性化合物,并且加成反应在乙腈中进行得很好如果HBF 4 ET 2 O的使用添加二烯之前质子化的偶氮化合物。由2,3-二氮杂双环[2.2.2] oct-2-ene(5)与1,3-环己二烯(6)和2,3-二氮杂双环[2.2.1]庚-2-衍生的中性肼的制备烯(10)与6和1,3-环庚二烯(7,11,和13,分别地)以及通过催化氢化衍生的(饱和肼9,12,和14,ropectively)的报告。10H +和环戊二烯的中性加合物15证明对分离太热不稳定,饱和形式16通过二酰亚胺还原15H +制备。中性肼都给予阳离子自由基和双阳离子与可感知的寿命的解决方案,和图9