The Diels-Alder Reaction of 2,4-Hexadien-1-ol with Maleic Anhydride: A Novel Preparation for the Undergraduate Organic Chemistry Laboratory Course

Abstract

The reaction of 2,4-hexadien-1-ol with maleic anhydride provides an excellent exercise for undergraduate laboratory courses. In addition to the expected Diels-Alder reaction, which takes place readily in refluxing toluene, subsequent intramolecular cleavage of the resulting bicyclic anhydride by the pendant hydroxy group generates a lactone. Thus, two important organic reactions can be carried out in a single laboratory session. The resulting product, which contains four new stereocenters, crystallizes upon cooling of the reaction mixture to give the pure product. Careful analysis of the 1H nuclear magnetic resonance spectrum, which contains a variety of cleanly split signals with no overlapping peaks, allows for assignment of all twelve hydrogens. A COSY spectrum of the product is also presented and interpreted.