Polar effects in the ruthenium(0)-catalysed reductive carbonylation of aromatic nitro derivatives to give ureas and amines

Several nitrobenzene derivatives were submitted to reaction with carbon monoxide in cis-cyclooctene in the presence of catalytic amounts of Ru3(CO)12. The corresponding ureas and amines were formed in this reaction, while secondary amines derived from insertion of the nitrene intermediate at the allylic position of cis-cyclooctene were secondary products. The influence of the electronic parameters of the substituents on the conversion and the urea vs. amine ratio is discussed. Hydrogen atoms seem to derive from the solvent