Introducing Complex NMR Mixtures at the Undergraduate Level: Isomerization, Separation and Analysis of the Diels-Alder Adducts from the Reaction of Methylcyclopentadiene and Maleic Anhydride (Part II)

This paper introduces undergraduate students to advanced NMR techniques to help elucidate the structures of endo and exo norbornene isomers formed during the Diels-Alder reaction between cyclopentadiene and methylcyclopentadiene with maleic anhydride. The microwave assisted isomerization of the norbornene derivatives resulted in a mixture of endo and exo isomers that were separated and analyzed using advanced NMR spectroscopy techniques, with a focus on the spectral interpretation and unequivocal assignment of the endo and exo stereoisomerism when possible.