Ammonium Ferrate-Catalyzed Cycloaddition of CO2 to Aziridines for the Synthesis of 1,3-Oxazolidin-2-ones

Simple ammonium ferrates are competent catalysts for the CO coupling with aziridines to yield 5-substituted 1,3-oxazolidin-2-ones. Good yields with remarkable selectivity are obtained under mild reaction conditions, room temperature, and atmospheric CO pressure, especially for non-hindered N-alkyl, N-benzyl and N-allyl aziridines, without the need of any co-catalyst. To shed light on the reaction mechanism, an extensive set of theoretical calculations has been carried out. A viable reaction mechanism involving just one ferrate molecule and where the rate determining step is the 1,3-oxazolidin-2-one ring closure has been found, and the corresponding barrier is compatible with the experimental conditions tested in this study.