New insight on the mechanism of 2-oxabicyclobutane fragmentation. A high-level ab initio study

High-level quantum chemical studies have been carried out to explain the unusual chemical reactivity of 2-oxabicyclobutane for the process of its fragmentation to acrolein. The predicted activation energy values for unimolecular and acid-catalysed fragmentation of OBB are high enough to rule out OBB intermediacy in the various thermal, photochemical and chemical reactions. These findings suggest that 2-oxabicyclobutane is so highly stable that there should be another mechanism of above mentioned reactions which leads to the formation of aldehydes and ketones.