Click the structures and reaction arrows in sequence to view the 3D models and animations respectively
Predict which product above is formed?
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 or for another example click here.
Note that the transition state is endo as expected.