Deprotonation of isoazatruxene enables photocatalytic arylation and phosphorylation of (hetero)aryl halides

Abstract

Isoazatruxene and its derivatives, which can be readily synthesized via cyclotrimerization, have been discovered as novel organic photocatalysts with high catalytic performance. However, the N-unsubstituted isoazatruxene (ITN-1) shows poor absorption in the visible region. Herein, we report that treatment of ITN-1 with Cs₂CO₃ generates the N-centered isoazatruxene anionic species (ITN³⁻), which exhibits enhanced visible-light absorption and potent reducing ability. Under the photocatalysis of ITN³⁻, the dehalogenative arylation and phosphorylation of aryl halides can be efficiently achieved, enabling the rapid assembly of pyrrole-containing biaryls and aryl phosphonates. The synthetic utility is further demonstrated by late-stage modification of complex molecules and multi-phosphorylation. Mechanistic studies confirm that the deprotonation of isoazatruxene results in enhanced visible-light absorption and improved photophysical properties.