摘要:
.alpha.,.delta.-Diethylenic carbonyl compounds of the formula ##STR1## are made by an oxy-Cope rearrangement of an acetylenic alcohol of the formula ##STR2## in the presence of a catalyst based on a metal of Group Ib of the periodic table or palladium. In the formulae (I) and (II), R.sub.1, R.sub.2, R.sub.3 and R.sub.4, which may be identical or different, each denote a hydrogen atom or a hydrocarbon radical R.sub.2 and R.sub.3 being capable together of forming an alkylene radical (--CH.sub.2 --).sub.n in which one or more carbon atoms may be substituted by one or more alkyl radicals containing 1 to 4 carbon atoms, n is 3 to 20 inclusively and R.sub.5 denotes a hydrogen atom.