A process for the manufacture of a product compound of the formula HC(R.sup.1).sub.2 C(R.sup.1).sub.2 C(R.sup.2).sub.2 C(R.sup.2).sub.2 H wherein each R.sup.1 is independently selected from the group consisting of H, F, Cl, CN, R, OR, CO.sub.2 R, C(O)R, OC(O)R, R.sup.f, OR.sup.f, CO.sub.2 R.sup.f, C(O)R.sup.f and OC(O)R.sup.f, where R is a hydrocarbyl group and R.sup.f is a C.sub.1 to C.sub.10 polyfluoroalkyl group, provided that at least one R.sup.1 is F, and wherein each R.sup.2 is independently selected from the group consisting of H, F, Cl, CN, R, OR, CO.sub.2 R, C(O)R, OC(O)R, R.sup.f, OR.sup.f, CO.sub.2 R.sup.f, C(O)R.sup.f, OC(O)R.sup.f and difunctional linkages where an R.sup.2 on each of two adjacent carbon atoms together form a link selected from the group consisting of --CH.sub.2 CH.sub.2 CH.sub.2 --, --CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2 --, --CH.sub.2 CH.sub.2 CH(CH.sub.3)--, --CH.sub.2 CH(CH.sub.3)CH.sub.2 --, --C(O)OC(O)--, and norborndiyl, comprising:
- (a) forming a metallacycle of the formula ##STR17## wherein R.sup.1 and R.sup.2 are as defined above, and wherein M is a metal selected from the group consisting of Group 8 metals, Group 9 metals, and Group 10 metals, L is a ligand selected from the group consisting of Group 14 ligands, Group 15 ligands, and Group 16 ligands, and m is an integer from 1 to 4, in the liquid phase by reacting a first olefinic reactant of the formula (R.sup.2).sub.2 C.dbd.C(R.sup.2).sub.2, a second olefinic reactant of the formula (R.sup.1).sub.2 C.dbd.C(R.sup.1).sub.2, and a metal complex soluble in the liquid phase of the formula M.sub.x L.sub.n, wherein x is an integer from 1 to 3 and n is an integer from 1 to 12;
- and
- (b) reacting the metallacycle in the liquid phase with hydrogen in the presence of ligand.