- Polyethylene-bound alkyl diaryl and triaryl phosphites that act as ligands for homogeneous nickel(0) butadiene cyclooligomerization catalysts are described. The homogeneous nickel(0) catalysts prepared in the presence of these ligands are shown to have the same product selectivity and reactivity as similar nickel catalysts prepared from low molecular weight phosphite ligands in reactions carried out at 100 C. By varying the ligand/nickel ratio, it is possible to vary the product selectivity of these polyethylene-bound nickel(0) catalysts. High product selectivities (>90%) for 1,5-cyclooctadiene are attainable. These ethylene oligomer ligated nickel(0) catalysts take advantage of the temperature-dependent solubility properties of polyethylene in order to maintain catalyst homogeneity at 100 C during the oligomerization. Recovery and recycling of the catalyst is possible because the catalyst and polyethylene quantitatively coprecipitate on cooling the reaction mixture to 25 C. 1986, American Chemical Society. All rights reserved.