The Diels-Alder reaction is a syn addition reaction with respect to both the diene and the dienophile. If the substituents in the dienophile are cis, they will be cis in the product; if the substituents in the dienophile are trans, they will be trans in the product.
The substituents in the diene will also maintain their relative configurations in the product.
A racemic mixture will be formed in Diels-Alder rxn.
Predicting the product when both reagents are unsymmetrically substituted Conformations of Dienes