A Ce-base-controlled and visible-light-induced approach enables the cleavage of NTf-pyridiniums into various 2-polyene sulfonylpyridines. This Zincke-like reaction involves the conversion of pyridines into electron-rich intermediates and subsequent regioselective electrophilic modification through the formation of an EDA complex, intermolecular single-electron transfer, radical coupling, and selective C2-N bond cleavage. In addition, the obtained 2-polyene sulfonylpyridine 2a displays interesting photophysical properties.
Shen et al. (Mon,) studied this question.