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

Abstract

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.

Keywords: carbon dioxide fixation; carboxylative cyclization; iodine; photocatalysis; radicals.