Synthesis of the Diels-Alder Adduct
Purpose: To investigate the methods behind Diels-Alder chemistry through the laboratory synthesis of 4- cyclohexene-cis- ,2-dicarboxylic anhydride from butadiene sulfone with maleic anhydride. By utilizing the theoretical concepts in a hands-on approach through laboratory synthesis, I hope to gain a better understanding of the reaction concepts governing Diels- Alder chemistry.
Theory: The Diels-Alder reaction is a cycloaddition, chemical reaction that occurs between a conjugated diene, a molecule with two alternating double bonds, and dienophile, an alkene, to form rings and bicyclic compounds. Because it involves the interaction of four π electrons that are supplied by the diene and the two π electrons supplied by the dienophile, the Diels-Alder reaction is often called [4 + 2] cycloaddition. In the reaction, two new σ bonds are formed and one π bond is formed at the expense of two π bonds, which results in a cyclic product. The Diels-Alder reaction is a member of a larger class of reactions called pericylic reactions, which are reactions that take place in a single step, without intermediates and that involve the flow or redistribution of bonding electrons. The reaction proceeds through a cyclic transition state and is concerted, meaning bonds in the transition state are simultaneously made or broken. The Diels-Alder reaction is favored when the dienophile is the substituted with electron withdrawing groups such as nitriles, amines, and carbonyls and is especially favored when it reacts with dienes that contain electron-donating groups like alkyls and alkoxy on the diene.
Diel’s Alder reactions have unique characteristics and requirements. Diels-Alder reactions are stereospecific, meaning cis-alkenes form cis-substituted products and trans-alkenes form trans-substituted products. The diene undergoes syn addition to the