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Abstract

A process is disclosed for preparing aliphatic compounds containing two conjugated double bonds cis-cis or cis-trans, characterized in that a compound of the general formula ##STR1## (in which R is H, alkyl from C.sub.1 to C.sub.10, or OY in which Y is a protective group selected from the class consisting of tetrahydropyranyl and 1-ethoxyethyl; X is an ester function selected from the class consisting of the acetates) is reacted with an alkyl-magnesium halide of the general formula: Z--Mg--R.sup.1 (II) (in which Z is chlorine, bromine or iodine, and R.sup.1 is a C.sub.1 -C.sub.10 alkyl group, or a group (CH.sub.2).sub.n OY in which Y has the same meaning as in formula (I), and n is a number from 3 to 10) in the presence of Li.sub.2 CuCl.sub.4, CuCl, CuBr, or CuI at temperatures ranging from about -30.degree. to +10.degree. C. in the presence of ethyl ether or tetrahydrofuran as solvent, to obtain an aliphatic compound of the general formula: R--CH.sub.2 --C.tbd.C--CH.dbd.CH--CH.sub.2 R.sup.1 (III) in which the carbon atoms linked with the double bond carry two hydrogen atoms in cis position, and reducing the triple bond of (III) with lithium-aluminum hydride to produce the trans-cis compound, or reducing (III) with dialkylborane or catecholborane to produce the cis-cis compound.

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First Claim