π-Allylic palladium complexes reacted with conjugateddienes to give diene-inserted products. Isoprene gave l,l-disubstituted allyl complexes rather than 1,2-disubstituted ones. Two types of allylic complexes were studied, and halogen-bridged dimer complexes showed lower reactivity than acetylacetonato complexes. When the allylic group or diene was varied, the reactivity decreased in the order: allyl