Metal cyanides nitrogen nucleophiles

It is well known that oxidation of carbamates leads to the formation of N-acyliminium ions via dissociation of the C-H bond a. to nitrogen. The electrochemical,4 metal-catalyzed,5 and chemical methods6 have been reported in the literature to accomplish this transformation. The transformation serves as a useful tool for organic synthesis, although only compounds of high oxidation potentials such as methanol and cyanide ion can be used as nucleophile. It... 

Due to the nucleophilicity of both carbon and nitrogen atoms in cyanides, numerous polymers with (M-CN M-) and (M-SCN- M) linkages are found. Examples include AgCN, 43, and AgSCN, 44, which exhibit low conductivities (— 10 i fi- cm" ) (46). One-dimensional cyano polymers with metals indifferent oxidation states have not been reported. Due to valence interchange these materials should exhibit a higher conductivity. 

There are exceptions to this rule, however, particularly when the electrons on the carbon of cyanide are tied up in a covalent bond. Both silver cyanide (AgCN) and cuprous cyanide (CuCN) have bonds between the metal and carbon (Ag-C or Cu-C) that have significant covalent character. The Ag and Cu ions are not charge dense, and they prefer to coordinate to atoms that are also not dense in charge (the C end of cyanide). If the metal-carbon bond in M-CN is covalent, the electrons on carbon are shared and less available for donation, which makes carbon less nucleophilic. In both AgCN and CuCN, the nitrogen atom is more nucleophilic and reaction with an alkyl halide R-X leads to a molecule called an isocyanide (or isonitrile, R-+N=C ). Isocyanides and the reaction of such compounds are not discussed in this hook. 

As noted above for reactions of [IPh2] salts with metal carbonyl anions, reactions do not always result in formation of new metal-carbon bonds. Thus, as shown in Scheme 38, [M(CN)(CO)5] reacts with 1(C = CR)Ph] in a manner consistent with nucleophilic attack by the nitrogen atom of the cyanide ligand. " Complex 67 (R = Ph) has been characterised by X-ray crystallography. For formation of the cyclobutenyl products 68 (M = Cr also characterised by X-ray... 

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