Click the structures and reaction arrows in sequence to view the 3D models and animations respectively
Working out regioselectivity
How is it possible to tell that the product above is formed, and not this regioisomer?
The regioselectivity of the reaction can be determined by working out where the largest component of the HOMO lies in the diene and the largest component of the LUMO lies in the dienophile. For more information on regioselectivity of the Diels-Alder reaction.