Chromium(III)-Catalyzed Addition of Water and Alcohol to α,β-Unsaturated Ketones for the Synthesis of β-Hydroxyl and β-Alkoxyl Ketones in Aqueous Media
An efficient chromium(III) chloride-catalyzed Michael-type reaction of water or alcohol with α,β-unsaturatedketones is developed. A variety of α,β-unsaturatedketones effectively reacted with either water or alcohols to give the corresponding β-hydroxyl ketones or β-alkoxyl ketones in modest to high yields with excellent compatibility to various functional groups. The approach was further utilized
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.