Photochemical formation of amides from t-butylamine and aromatic aldehydes and ketones

Irradiation of benzaldehyde, substituted benzaldehydes, benzoin, benzil, and t-butyl phenyl ketone in the presence of t-butylamine leads to N-t-butylarenecarboxamides. In the case of the aldehydes, imine formation also occurs. The imine is reduced by reaction with α-hydroxybenzyl radicals, which are also generated in the photochemical reaction. Benzyl phenyl ketone does not give products via and α-scission reaction, but instead is reduced by the amine. The formation of the amides is rationalised as occurring by attack of benzoyl radicals on the amine.