Visible light-induced synthesis of (Z)-β-iodoenamides from N-vinyl amides mediated by the ion pair charge transfer state

A facile and novel approach for the highly chemo- and stereoselective synthesis of (Z)-β-iodoenamides from N-vinyl amides has been developed based on a visible-light-induced ion pair charge transfer state derived from pyridinium iodides. The obtained (Z)-β-iodoenamides were effectively transformed into various useful molecules. The detailed reaction mechanism was further investigated through control experiments, radical capture, and UV–Vis spectroscopy, which indicated that pyridinium iodide acted as both a photosensitizer for radical generation and an iodine source during the process.