Effect of Sustainable and Confined Media on the Photoinduced [6π]‐Electrocyclization Reaction of Diphenyl and N‐Methyldiphenylamines

A systematic investigation of the photoinduced [6π]‐electrocyclization reaction of diphenylamine and N‐methyldiphenylamine has been carried out under steady‐state and time‐resolved conditions in homogeneous (cyclohexane, acetonitrile and methanol) and micellar solutions (sodium dodecyl sulfate ‐SDS, cetyltrimethylammonium chloride‐CTAC and polyethylene glycol monododecyl ether‐Brij P35). The photolysis of such compounds in both homogeneous and micro‐heterogeneous media afforded the corresponding carbazoles in almost quantitative yield under oxidative conditions. Furthermore, the relative rate of formation of the photoproducts increases when moving from homogeneous media to micellar solution, due to the environmental confined and hydrophobic micellar core as highlighted by 1D and 2D NMR (NOESY and DOSY) spectroscopic analyses. A deep insight on the photoinduced [6π]‐electrocyclization reaction of diphenylamine and N‐methyldiphenylamine has been carried out under steady‐state and time‐resolved conditions in homogeneous and micellar solutions. The micelles’ effect on the photolysis of such compounds has been ascertained. Triplet states and 4a,4b‐dihydrocarbazole intermediates were detected in both media and the location of the substrates within the hydrophobic micellar core using 2D NMR spectroscopy was successfully achieved.