Synthesis and Low Temperature Spectroscopic Observation of 1,3,5-Trioxane-2,4,6-Trione: The Cyclic Trimer of Carbon Dioxide

1,3,5-Trioxane-2,4,6-trione (cyclic trimer of CO<sub>2</sub>) is the product of a four-step synthesis: chlorination of isobutyraldehyde; cyclotrimerization of 2-chloro-2-methylpropanal; dehydochlorination of 2,4,6-tris­(2-chloropropan)-2-yl-1,3,5-trioxane; ozonolysis at −80 °C of 2,4,6-tri­(propan-2-ylidene)-1,3,5-trioxane. This trioxane-trione is detected in solution at temperatures between −80 to −40 °C, and its conversion to CO<sub>2</sub> is monitored by <sup>13</sup>C NMR and FTIR. The CO<sub>2</sub> trimer has a half-life of approximately 40 min at −40 °C.