Ritter reaction polarity

A number of polar additions to unsaturated polymers are known. These include Michael additions, hydroboration, 1,3-dipolar additions, ene reaction, the Ritter reaction, Diels-Alder additions, and others. 

Cristol has earned out photochemical studies on a range of cyclic halogenated substrates which yield Ritter-type products.Irradiation of the dihalides (80) in acetonitrile normally affords a mixture of the isomeric piquets (81) and (82 X = halogen), plus polar material. However, when the solvent was switched to 3% aqueous acetonitrile, significant amounts of the additional products (81 X = OH 13%) and (81 X = NHAc 16%), plus traces of (82 X = NHAc) were isolated (equation 40). These new substances are believed to result from nucleophilic attack by water or acetonitrile on a ground state carbe-nium ion-like intermediate. A number of further, closely related reactions of this type have been described.These photolyses consistently yield amide products but, unfortunately from the synthetic viewpoint, mixtures are often produced, and overall yields of the amides are not generally high. 

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