The aminocarbonylation of phenylacetylene has been studied in the presence of the catalytic system formed by palladium acetate in combination with (2-pyridyl)diphenylphosphine and methanesulfonic acid. The catalytic activity is strongly influenced by the nature of the amine: good reaction rates are achieved using amines of low basicity such as aniline. The reaction solvent influences both the activity and the selectivity of the catalyst: the highest reaction rates accompanied by complete regioselectivity towards the branched amide are obtained working in dichloromethane/N-methylpyrrolidinone mixtures. Also the acid to palladium molar ratio and the P(CO) affect to a lower extent the process: the highest catalyst activity is obtained operating at a methanesulfonic acid/Pd molar ratio of 30:1 and at P(CO) = 20 atm. (C) 2004 Elsevier B.V. All rights reserved.