Palladium catalyzed addition of certain carbon pronucleophiles 2 to conjugated enynes 1 afforded the corresponding allenes 3 in good to excellent yields. The most reactive methynes such as methylmalononitrile 2c enabled to undergo double addition leading to alkenes 4. Catalyst optimization supported Pd-2(dba)(3) . CHC3 - dppf combination as the best system among all catalysts tested. The plausible mechanisms for these catalytic reactions were proposed. (C) 1997 Elsevier Science Ltd.