Question: are endo and exo enantiomers?
Answer: The endo and exo products are formed as two enantiomers depending on the alignment of the diene and dienophile: And any combination of an endo and exo product represents a pair of diastereomers: If the diene is also unsymmetrical, then you need to consider the regiochemistry of the Diels-Alder as well.