Imidazolidinium, tetrahydropyrimidinium and benzimidazoliumsalts were prepared. Upon reaction with tBuOK, they generate carbene ligands, which were associated in situ to [RuCp*(MeCN)3]PF6 to produce ruthenium catalysts that are active for the substitution of allylic substrates by dimethyl malonate as a carbonucleophile and phenol. The influences of the N-heterocyclic structures, as well as that of