Sulphonyl cyanides, reactions

Primary aliphatic amines may be oxidized to nitriles [151]. A new catalyst of this reaction is cobalt oxide prepared from cobalt (II) sulphate and sodium hydroxide [155]. Benzylamine dissolved in boiling benzene containing the catalyst is converted to benzonitrile in 85% yield when oxygen is bubbled through the solution. Arylsulphonyl cyanides may be prepared [156] in good yields by oxidation of the thiocyanates with 3-chloroperbenzoic acid in hexane at 60°. An aliphatic thiocyanate gave a low yield of the sulphonyl cyanide. 

The carbon—sulphur bond is fractured in the reaction of p-toluene-sulphonyl cyanide with sodium ethanethiolate in ethanol. Other thiols, not thiolates, can also fracture the carbon—sulphur bond . ... 

Sulphonyl Cyanides.—Arylsulphonyl cyanides are more reactive than aroyl cyanides in cycloaddition reactions, because of delocalization of CN TT-charge density this is illustrated by their cycloaddition to 5,5-dimethoxy-tetrahalogeno-cyclopentadienes. Olefins give jS-cyano-sulphones under irradiation (254 nm), e.g. ArS02CH2 CH(CN) (CHa)3Me from hex-l-ene. ... 

The Michael-type addition, a nucleophilic addition of an anion to the carbon-carbon double bond of an a,(3-unsaturated ketone, aldehyde, nitrile, nitro, sulphonyl, or carboxylic acid derivative, provides a powerful tool for carbon-carbon bond formation. The reaction is most successful with relatively nonbasic ( soft ) nucleophiles such as thiols, cyanide, primary and secondary amines, and P-dicarbonyl compounds. There is often a competition between direct attack on the carbonyl carbon (1,2-addition) and conjugate addition (1,4-addition) when the substrate is an a,(3-unsaturated carbonyl compound. 

This method is particularly suitable for the synthesis of a-ethylenic and aromatic acyl cyanides but it also provides a valuable method of preparing certain aliphatic acyl cyanides (Table 6.6). The reaction fails with acryloyl chloride, sulphonyl chlorides, ethyl chloroformate and oxalyl chloride. 

A sulphonyl analogue of the normal Reissert compound has been postulated as an intermediate for the reaction in which isoquinoline is converted to 4-chlo-ro-l-cyanoisoquinoline (or 1-cyanoquinoline, in the presence of potassium hydroxide) on reaction with sulphuiyl chloride and potassium cyanide in water at 0° [114]. The yield is poor. 

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