Pyrimidopteridine N‐Oxide Organic Photoredox Catalysts: Characterization, Application and Non‐Covalent Interaction in Solid State.

Herein we report the photo‐ and electrochemical characterization of pyrimidopteridine N‐oxide‐based heterocycles. The potential of their application as organic photoredox catalysts is showcased in the photomediated contra‐thermodynamic E→Z isomerization of cinnamic acid derivatives and oxidative cyclization of 2‐phenyl benzoic acid to benzocoumarin using molecular oxygen as a mild oxidant. Furthermore, unprecedented intermolecular non‐covalent n–π‐hole interactions in solid state are discussed based on crystallographic and theoretical data. PyrimidopteridineN‐oxide‐based heterocycles exhibit excellent excited state reduction potentials paired with a suitable ground state reduction potential allowing for catalyst turnover with mild oxidants. The structural similarity between pyrimidopteridines and recently uncovered flavine N‐oxides may draw an important link between organic photoredox catalysis and chemical biology. [ABSTRACT FROM AUTHOR]