Metal-Free Photocatalytic Synthesis of exo-Iodomethylene 2-Oxazolidinones: An Alternative Strategy for CO2 Valorization with Solar Energy.

A visible-light-promoted metal-free carboxylative cyclization of propargylic amines with CO2 was shown to offer exo-iodomethylene 2-oxazolidinones. Incorporation of both CO2 and iodo moieties into these compounds was realized efficiently. The mechanism study revealed that this carboxylative cyclization proceeds through a radical pathway. Notably, the iodine-functionalized 2-oxazolidinone as a platform molecule could be easily converted into a wide range of value-added chemicals through Buchwald-Hartwig, Suzuki, Sonogashira, photocatalytic ene, and photoreduction reactions. As a result, the plentiful downstream transformations remarkably enhance the range of chemicals derived from CO2 and open a potential avenue for CO2 functionalization to circumvent energy challenges in this field.