Catalytic hydrocyanation of alpha-ketoalkynes by Ni(CN)(2)/CO/KCN system in alkaline aqueous media: Identification of the active species

5-Hydroxy-3-pyrrolin-2-ones are regioselectively synthesized in a good yiel d under very mild conditions by tetracyanonickelate (0) ion catalyzed hydro cyanation of alpha-ketoalkynes, in the absence of hydrogen cyanide. The cat alyst is prepared in situ in a basic aqueous medium by reduction of Ni(CN)( 2) with CO in the excess of KCN. From the LR spectroscopy studies and by ev aluation of catalytic activity of some cyanonickelates it is proposed that [Ni(CN)(4)](-4) anion is the active species in the process. A possible mech anism is suggested for the conversion of nickel cyanide to [Ni(CN)(4)](-4). The effect of the reaction variables, e.g.: reaction time, temperature, ab sorption of carbon monoxide, the concentration of potassium cyanide, water, substrate, and sodium hydroxide were also examined. (C) 2000 Elsevier Scie nce B.V. All rights reserved.