Theoretical study on cycloaddition of singlet dichlorocarbene with formaldehyde, acetaldehyde and benzaldehyde and subsequent rearrangement reactions

Cycloaddition reactions of the singlet CCl₂ carbene with H ₂CO, CH₃CHO and C₆H₅CHO and the subsequent rearrangement processes have been investigated with density functional theory. It was found that the interaction between the σ orbital of CCl₂ and the C=O π* orbital plays an important role in the cycloaddition reactions. The addition reaction of CCl₂ with H₂CO proceeds very easily, which is slightly influenced by the methyl and phenyl substitutions. However, the substitutions significantly reduce the barrier to the rearrangement reactions. The interaction between solvent and solute has a little influence on the structures of the stationary points, but has a noticeable influence on the barrier heights of the rearrangement reactions.