The hydration of chloroacetonitriles catalyzed by mono- and dinuclear Ru(II)- and Os(II)-arene complexes.

The hydration of nitriles to the corresponding amides is an important reaction for both laboratory and industry purposes. The classical synthesis method requires harsh conditions, gives low yields, and is nonselective due to further hydrolysis of the amides into carboxylic acids. To obtain good yields and high selectivity, transition metal complexes have been utilized as catalysts for this transformation. Herein, a series of Ru(II)- and Os(II)-arene complexes--based on pyranone, thiopyranone, and pyridinone ligands--were assayed on the hydration of chloroacetonitriles. The influence of the substitution pattern of the ligand, and of the nuclearity and of the type of substrate on the yield, the selectivity, and the turnover numbers are discussed.