Cyanation and Isonitrile Addition

Dinitrogen cleavage can also be achieved by addition of KH to [(ONO)V (thf)] (where ONO = 2,6-(3- Bu-5-Me-2-OC6H2CH2)2-4- Bu-(p-tolyl) NC6H4 ) (54) under an atmosphere of N2 to give the V(IV) nitrido dimer (55) that can be oxidized to the V(V) nitrido species (56) (Scheme 21). Compound 56 reacts readily with CO and isonitriles to form the cyanate (57) and carbodiimide (58) complexes, respectively. The cyanate species 57 releases KNCO on alkyne addition to form 59, which converts to 54, when dissolved in THF and thereby closing the cycle. 

The various classes of compounds featuring carbon-nitrogen multiple bonds that are substrates for organometallic addition comprise azomethines, immonium ions, nitrones, hydrazones, oxime ethers, amidinesimidoyl halides, nitriles, isonitriles, and cyanates. Dicyclohexylcarbodiimide is omitted here because it has been included in the carbonyl section (p.l 16) side by side with isocyanates and isothiocycanates. 

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