Photo-induced Polar Addition of Protic Solvents to Cycloalkenones. Evidence for the Ground-state<i>trans</i>Isomers as Chemically-reactive Intermediates
作者:Ryoji Noyori、Masao Katô
DOI:10.1246/bcsj.47.1460
日期:1974.6
The photo-induced reaction of cyclic α,β-unsaturated ketones with protic media is described. The irradiation of 2-cycloheptenone or 2-cyclooctenone in various protic solvents (alcohols, acetic acid, water, and diethylamine) results in the formation of Michael-type solvent adducts. The chemically-reactive species have been demonstrated to be the highly strained trans isomers in a ground state. The irradiation of cis-2-cyclononenone affords the stable trans isomer, which reacts in the dark with methyl alcohol at an elevated temperature to give 3-methoxycyclononanone. The irradiation of 2-cyclohexenone in methyl alcohol yields 3-methoxycyclohexanone in a poor yield. The possible existence of trans-2-cyclohexenone is discussed.
本文描述了环α、β-不饱和酮与原生介质的光诱导反应。2-cycloheptenone 或 2-cyclooctenone 在各种原生溶剂(醇、乙酸、水和二乙胺)中照射后会形成迈克尔型溶剂加合物。化学反应物种已被证明是处于基态的高应变反式异构体。辐照顺式-2-环壬酮会产生稳定的反式异构体,该异构体在黑暗中与甲醇在高温下发生反应,生成 3-甲氧基环壬酮。在甲醇中辐照 2-环己烯酮会产生 3-甲氧基环己酮,但产量很低。讨论了反式-2-环己烯酮的可能存在。