Hydrogenation of nitriles with iridium-triphenylphosphine complexes

Abstract

Reactions of cationic iridium(I)-COD (COD = 1,5-cyclooctadiene) complexes, [Ir(COD)(PhCN)(PPh3)]ClO4 (1), [Ir(COD)(PPh3)2]ClO4 (2) and [Ir(COD)(PhCN)2]ClO4 (3) with nitriles under H2 catalytically produce primary, secondary and tertiary amines. Hydrogenation of nitriles (RCN) gives HCl salts of amines (RCH2NH2HCl, (RCH2)2NH HCl) in CH2Cl2. Secondary and tertiary amines seem to be produced by the reactions of RCN with primary and secondary amines, respectively under H2 in the presence of catalysts. The hydrogenation in the presence of1 and2 is homogeneously catalyzed by soluble iridium-PPh3 complexes formed in the reactions of1 and2 with H2 and RCN whereas the hydrogenation in the presence of3 is heterogeneous by metallic iridium powders produced in the reduction of3 by H2.