The Diels—Alder Reaction of Cyclopentadiene with Maleic Anhydride

The Diels—Alder Reaction of Cyclopentadiene with Maleic Anhydride 

Cyclopentadiene and maleic anhydride react readily in a Diels—Alder reaction to form the adduct, ds-norbornene-5,6-endo-dicarboxylic anhydride  

Because two molecules of cyclopentadiene can also undergo a Diels-Alder reaction to form dicyclopentadiene, it is not possible to store cyclopentadiene in the monomeric form. Therefore, it is necessary to first crack dicyclopentadiene to produce cyclopentadiene for use in this experiment. This will be accomplished by heating the dicyclopentadiene to a boil and collecting the cyclopentadiene as it is formed by fractional distillation. To keep it from dimerizing, the cyclopentadiene must be kept cold and used fairly soon. 

The cracking of dicyclopentadiene should be performed by fhe insfrucfor or laboratory assisfant. If a flame is used for fhis, be sure fhaf fhere are no leaks in fhe sysfem, because bofh cyclopentadiene and fhe dimer are highly flammable. The procedure provides enough cyclopenfadiene for abouf 50 sfudents. 

Dispose of the mother liquor from the crystallization in the container designated for nonhalogenated organic solvents. 

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EXPERIMENT 47 The Diels—Alder Reaction of Cyclopentadiene with Maleic Anhydride 423... 

Extended Hiickel Theory has been used to calculate an approximate energy surface for the [1,3] sigmatropic rearrangement connecting (171) to (172). The calculated relative ease of the various reaction paths is correlated with both the experimental data and the predictions of orbital symmetry theory. A non-coplanar transition state in the Diels-Alder reaction of cyclopentadiene with maleic anhydride, or with other five-membered cyclic dienophiles of C2 symmetry, is suggested by the relationship between the primary and secondary overlap integrals in the Salem-type analysis of the reaction path. ... 

In the Diels-Alder reaction of cyclopentadiene with maleic anhydride the major product is the one in which the anhydride group, o assumed the endo... 

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