Heterocyclic Photochemistry in Contrast with Carbon Behavior. Regioselective Photochemical Rearrangement of an Azacyclohexadienone: Mechanistic and Exploratory Organic Photochemistry

The Type-A photochemistry of cyclohexadienones is well-studied and follows a well-established mechanistic pathway. One early example is the rearrangement of santonin to lumisantonin. Another example is the rearrangement of 4,4-diphenylcyclohexa-1,5-dienone. Remarkably, replacement of one carbon by nitrogen alters the reaction course to give a regioselective phenyl migration.