Final answer:
The reaction between maleic anhydride and cyclopentadiene results in the formation of endo-cis-5-norbornene-2,3-dicarboxylic anhydride, through a Diels-Alder cycloaddition process.
Step-by-step explanation:
When maleic anhydride and cyclopentadiene react, the major product is a compound called endo-cis-5-norbornene-2,3-dicarboxylic anhydride. This reaction is an example of a Diels-Alder reaction, which is a concerted organic chemical reaction (specifically a [4+2] cycloaddition) between a conjugated diene and a substituted alkene, commonly referred to as the dieneophile, to form a cyclohexene system.
In the case of maleic anhydride and cyclopentadiene, the former acts as the dieneophile and the latter as the diene. The reaction typically favours the endo product due to secondary orbital interactions that stabilize the transition state leading to it.