ORTHOMETALLATED RUTHENIUM-COMPLEX-CATALYZED REDUCTIVE CARBONYLATION OF NITROAROMATICS

Orthometalated ruthenium(II) complexes of the type [RuL(CO)2Cl]2 LH=2- phenylpyridine, 1-phenyl pyrazole, azobenzene and benzo(h) quinoline) behaved as efficient catalysts for the reductive N-carbonylation of ni troaromatics in mild coordinating solvents containing alcohol and a ba sic cocatalyst under high pressure, high temperature conditions. The p roducts were mainly the corresponding N-phenylcarbamates and aniline w ith a small amount of azobenzene detected in some isolated cases. The effects of various reaction parameters such as P(CO), temperature, con centration of alcohol and cocatalysts on the nature and yields of prod ucts have been studied. A tentative reaction mechanism has been propos ed on the basis of experimental findings.