SELECTIVE OLIGOMERIZATION OF PHENYLACETYLENE TO 1,2,4-TRIPHENYLBENZENE CATALYZED BY Ni(CO)3(P(O-i-C3H7)3.

Article abstract of DOI:10.1016/0304-5102(85)80017-1

The Ni(0) monophosphite complex, Ni(CO)//3L, where L equals P(O-i-C//3H//7)//3, oligomerizes phenylacetylene to 1,2,4-triphenylbenzene with a selectivity greater than 95%. The reaction when carried out in boiling benzene shows a high activity for the catalyst, typically 200 mol alkyne per 1 mol Ni h** minus **1. Below 70 degree C the reaction does not proceed at all for substrate/catalyst molar ratios of the order of 300. Increasing the temperature increases the conversion of the substrate and decreases the induction period. Experiments carried out in the presence of CO and free L show a decreased reaction rate, indicating a possible competition of these ligands with the alkyne for the catalyst.