Single electron transfer photoinduced oxidation of piperidine and pyrrolidine derivatives to the corresponding lactams

Abstract

Irradiation by visible light of various N-arylaminopiperidines or N-arylaminopyrrolidines in presence of a catalytic amount of photosensitizer led with good yields to the corresponding N-arylaminolactams under mild conditions. This reaction proceeds by two consecutive photooxidations, the first in presence of trimethylsilyl cyanide and the second one in presence of water. Voltammetric investigations demonstrated clearly that hydrazines are more readily oxidised than tertiary amines, and as a consequence it is possible to obtain by photooxidation a wider range of oxidised compounds.