Abstract Imidazolidinium, tetrahydropyrimidinium and benzimidazolium salts were prepared. Upon reaction with tBuOK, they generate carbene ligands, which were associated in situ to [RuCp*(MeCN) 3] PF 6 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 the benzylic N-substituents, on the ...