Process for the preparation of alpha , delta -diethylenic carbonyl compounds

摘要

alpha , delta -Diethylenic carbonyl compounds of the formula <IMAGE> (I) are made by an oxy-Cope rearrangement of an acetylenic alcohol of the formula <IMAGE> (II) 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), R1, R2, R3 and R4, which may be identical or different, each denote a hydrogen atom or a hydrocarbon radical R2 and R3 being capable together of forming an alkylene radical (-CH2-)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 R5 denotes a hydrogen atom.