Pericyclic Reactions: Cycloadditions and Diels-Alder Reaction
Cycloadditions: Scope of the Diels-Alder Reaction
In most cases, the dienophile carries electron-withdrawing substituents, thereby accelerating the reaction (also see Reactivity of Cycloadditions). Electron-poor alkines are also suitable dienophiles giving rise to 1,4-cyclohexadienes. Similarly reactive are electron-poor heterodienophiles such as nitroso compounds. Following are some examples illustrating the broad scope of the Diels-Alder reaction.