The key role of water in the heterogeneous permanganate oxidation of ω-hydroxy alkenes
作者:Sundarababu Baskaran、Imadul Islam、Padma S. Vankar、Srinivasan Chandrasekaran
DOI:10.1039/c39900001670
日期:——
Potassium permanganate–copper sulphate in dichloromethane in the presence of a catalytic amount of water effects a smooth oxidative cyclization of ω-hydroxyalkenes to ω-lactones in good yields with the net loss of one or more carbon atoms in the process.
Cyclization of geraniolene and competitive cyclization-cyclialkylation of some phenyl derivatives
作者:B.C. Roest、J.U. Veenland、Th.J. de Boer、E. Lodewijk、J. de Leeuw
DOI:10.1016/0040-4020(68)88117-7
日期:1968.1
The cyclization of geraniolene (1; 2,6-dimethyl-1,5-heptadiene) to the isomeric cyclogeraniolenes (3, 4, 5) with aqueous sulphuric acid as a catalyst proceeds partly via 2,2,6,6-tetramethyltetrahydropyran (8).
A variety of aldehydes undergo a smooth coupling with 6-methylhept-5-en-2ol in the presence of molecular iodine to afford the 2,3,6-trisubstituted tetrahydropyrans in good yields through 3,5-oxonium-ene cyclization under mild and neutral conditions. This method is simple, convenient, and cost-effective. (C) 2013 Elsevier Ltd. All rights reserved.
A general approach to the synthesis of butanolides: synthesis of the sex pheromone of the Japanese beetle