Alkyl/Glycosyl Sulfoxides as Radical Precursors and Their Use in the Synthesis of Pyridine Derivatives

We report here the use of simple and readily available alkyl sulfoxides as precursors to radicals and their application in the preparation of pyridine derivatives. We show that alkyl sulfoxides, N-methoxy pyridinium salts and fluoride anions form electron donor-acceptor (EDA) complexes in solution, which, upon visible light irradiation, undergo a radical chain process to afford various pyridine derivatives smoothly. This reaction displays broad scope with respect to both sulfoxides and N-methoxy pyridiniums. The synthetic versatility of sulfoxides as a handle in chemistry adds to their power as radical precursors. Glycosyl sulfoxides are converted to the corresponding pyridyl C-glycosides with high stereoselectivities. Computational and experimental studies provide insights into the reaction mechanism.

Automated summary

This research presents the use of alkyl sulfoxides as precursors to radicals in the synthesis of pyridine derivatives. It demonstrates that alkyl sulfoxides, N-methoxy pyridinium salts, and fluoride anions form electron donor-acceptor complexes in solution, which can undergo a radical chain process upon visible light irradiation to produce various pyridine derivatives efficiently. The broad scope of this reaction extends to different sulfoxides and N-methoxy pyridiniums. The synthetic versatility of sulfoxides as radical precursors adds to their significance as a useful tool in chemistry.