Reagents. 1, 3-and 1, 4-Cyclohexadienes were purified by distillation from calcium hydride under nitrogen. Cyclooctane was distilled prior to me. 1, 3-Diaminopropane (DAP) was distilled from calcium oxide and stored over 3A molecular sieves. 18-Crown-6 was purified by means of ita acetonitrile complex, 20 mp
