Aziridines. Part 60. Electron transfer from radical anions to N-alkanoylaziridines. Exocyclic cleavage of an aziridino ketyl

Abstract

Reactions of non-aromatic N-acylaziridines with radical anions yield products arising from the intermediate β-amidatoalkyl radicals that are generated by homolytic ring opening of the first formed aziridino ketyls. Reduction of these radicals and their combination with the radical anion show a dependence on the nature of the radical anion (naphthalenide, anthracenide) similar to the known reactions of these radical anions with alkyl halides, i.e.(nearly) no reduction by anthracenide. This contrasts with the published 37% reduction in the reaction of anthracenide with an N-benzoylaziridine. Very rapid mixing of the reagents by an injection technique changes the product mixture in a manner that points to a reduction by the aziridino ketyl which has a very short lifetime if derived from a non-aromatic acyl group. It is shown that an aziridino ketyl can undergo exocyclic cleavage of the bond next to the ketyl carbon provided that the eliminated carbanion (R^– of the acyl group RCO) is stabilized such as by two phenyl groups in the reported example.