A Photo-Smiles Rearrangement: Mechanistic Investigation of the Formation of Blatter Radical Helicenes.

ABSTRACT: Photocyclization of 8-aryloxy-3-phenylbenzo[e][1,2,4]triazines leads to helicene radicals. Structural analysis of radicals leuco forms by two-dimensional correlation nuclear magnetic resonance methods demonstrated that the photocyclization involves a Smiles rearrangement and exclusive formation of a single rearranged product for all substrates. Density functional theory investigations indicate that the mechanism requires the T₁ state with (n, π*) character localized on the benzo[e][1,2,4]triazine (BT) fragment and at least one occupied π molecular orbital (MO) localized on the aryloxy fragment with an energy that is higher than that of the n MO. This electronic structure is favorable for aryl-to-BT single-electron transfer and formation of a zwitterion, whic

SUBMITTER: Singh HK 

PROVIDER: S-EPMC11833871 | biostudies-literature | 2025 Feb

REPOSITORIES: biostudies-literature