Ritter-type reactions amide synthesis

Olah, G. A., Gupta, B. G. B., Narang, S. C. Synthetic methods and reactions 66. Nitrosonium ion induced preparation of amides from alkyl (arylalkyl) halides with nitriles, a mild and selective Ritter-type reaction. Synthesis 274-276. 

Due to the important role of nitrogen functional groups, the addition reactions of an electrophilic selenium reagent and a nitrogen nucleophile to a carbon-carbon double bond represent a synthetically relevant process with potential practical applications. Among the reactions of this type which have been described already, perhaps the most important contribution is represented by the Ritter-type amide synthesis described by Toshimitsu and Uemura [48a, 48b]. The addition of a phenylselenyl and of an acylamino group to a mono or a 1,2-disubstituted olefin was accomplished by treating the olefin with PhSeCl in acetonitrile and water in the presence of trifluoromethanesulfonic acid. 

Sodium superoxide in DMSO is a useful reagent for converting nitriles into amides. Isolated yields are above 70% for this reaction, which was unexpected as nitriles are inert to Na02 in other solvents. The mechanism is not completely understood. The Ritter-type synthesis of N-alkyl-amides from nitriles and alcohols can be improved by the addition of metal carbonyls to help stabilize the intermediate carbonium ions, and an alternative approach is to treat a nitrile with an alkyl halide and nitrosonium hexafluorophosphate. ... 

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