The use of a catalytic amount of nickelbis(1,4-bis(diphenylphosphino)butane) in DMF enables the activation of the C-C bond in dimethyl allylmalonate derivatives to proceed under rather smooth reaction conditions, without added nucleophile. Several examples like isomerization of substituted-allyl malonate derivatives, racemization of chiral products, but also a synthetic application as an inverse disproportionation reaction are described. (C) 1997, Elsevier Science Ltd.