HOMOGENEOUS CATALYTIC REDUCTIVE CARBONYLATION OF ORGANIC NITRO COMPOUNDS: BIDENTATE NITROGEN LIGANDS AS A KEY POINT

The reductive carbonylation of nitro compounds is a process with a high potential synthetic and industrial interest, since many products can be obtained from nitro compounds and CO, including isocyanates, carbamates, ureas and heterocyclic compounds. The most active systems in this kind of reactions are based on the use of a transition metal catalyst and a nitrogen ligand. In this PhD thesis studies on reduction by carbon monoxide of palladium complexes relevant to the reaction of carbonylation of nitroarenes are reported. Moreover catalytic studies were conducted on the use of differently substituted nitrogen ligands in the palladium catalyzed synthesis of methyl N-phenylcarbamate. In particular the effect of non symmetric ligands on the activity of the catalytic system and the use of long alkyl chain substituted phenanthrolines for catalyst recycling are discussed. A system based on a palladium/phenanthroline complex was also investigated for the reductive cyclization of beta-nitrostyrenes to indoles: the optimization of the reaction and its scope are reported.