Reaction pathways of the [2Â +Â 2] cycloaddition between formaldehyde with ketene and isocyanic acid: A theoretical investigation

A computational study of the [2 + 2] cycloaddition reaction pathways for formaldehyde-ketene and formaldehyde-isocyanic acid has been presented by using the DFT(B3LYP) method. These cycloaddition reactions could yield to eight different four-membered molecules. In the two considered reactions, the reactions for the β-propiolactone and oxazetidinone products have the lower barriers of 26.40 and 32.88 kcal mol−1 and are exothermic by 27.68 and 4.00 kcal mol−1, respectively. The β-propiolactone and oxazetidinone ring compounds have been predicted to be the most stable thermodynamically. Simulation of the solvent environment (toluene, THF, acetone, acetonitrile and water) has been investigated by using polarized continuum model method, yet only small differences have been found to occur in energetics between the studied structures in the gas-phase and in the solvent.