A Metal-Free Synthesis of N -Aryl Oxazolidin-2-ones by the One-Pot Reaction of Carbon Dioxide with N -Aryl Aziridines

The cost-effective TPPH₂/TBACl-catalyzed (TPPH₂ = dianion of tetraphenyl porphyrin; TBACl = tetrabutyl ammonium chloride) carbon dioxide cycloaddition to N -aryl aziridines was successful in synthesizing N -aryl oxazolidin-2-ones. A catalytic tandem reaction was also developed, in which N -aryl aziridines were initially synthesized and then reacted with carbon dioxide without being purified. The procedure occurred with a very high atom economy, molecular nitrogen being the only by product of the entire tandem process. In addition, the mechanism of catalytic cycle was investigated by DFT calculations.