Three-Component Synthesis of Oxazolidinones via Phosphine-Catalyzed Fixation of Carbon Dioxide and Mechanistic Investigation in Mass Spectrometry

A phosphine-catalyzed three-component cyclization reaction between anilines, carbon dioxide, and chloroalkanes was developed for the synthesis of oxazolidinones. This strategy not only proceeds under ambient CO₂ pressure and metal-free condition but also shows a broad substrate scope, including aromatic amines, aliphatic amines, chiral amino acid esters, and bioactive molecules, providing an efficient and environmentally benign route to synthesize pharmaceutically relevant <i>N</i>-aryl-oxazolidinones. Mechanistic investigations utilizing mass spectrometry (MS) indicate the involvement of multiple phosphine intermediates in this process, thereby elucidating the underlying mechanism. Moreover, the relationships between these phosphine intermediates and Tolman cone angles or the solvent effect of phosphines were examined through mass spectrometry.