The mechanism of the reaction between an aziridine and carbon dioxide with no added catalyst

The mechanism of the reaction at room temperature between an unactivated 2‐alkyl aziridine and carbon dioxide to generate the corresponding oxazolidinone in glass has been studied. Theoretical calculations suggest that this reaction should not proceed at room temperature in the absence of a catalyst. In cases where a reaction was observed, kinetic studies show that the reaction displays a zero‐order dependence with respect to aziridine, indicating that free aziridine is not involved in the rate‐determining step. An ammonium salt generated in situ acts as a catalyst. The amount of this catalyst is diminutive, which prevented spectroscopic identification, and it is not readily removed from the starting material using chromatography. The mechanism of the reaction between a 2‐alkyl aziridine and CO2 to generate an oxazolidinone has been studied. Calculations suggest that this reaction should not proceed at room temperature in the absence of a catalyst. Kinetic studies show that the reaction displays a zero‐order dependence with respect to aziridine, indicating that free aziridine is not involved in the rate‐determining step. A small amount of an ammonium salt generated in situ acts as a catalyst.