Draw the reactants that would be used to form this cyclohexene derivative in a Diels-Alder reaction. Include any relevant stereochemical configurations. I I 1 I I L Drawing O 1

Although the Diels–Alder reaction generally occurs between an electronrich diene and an electron-deficient dienophile, it is also possible to have inverse-demand Diels–Alder reactions between suitable electrondeficient conjugated double bonds and electron-rich alkenes. These reactions are particularly useful because they allow for the incorporation of heteroatoms into the new six-membered ring. Predict the products of each inverse-demand Diels–Alder reaction below. Be sure your products reflect the correct stereochemistry. If more than one regioisomer is possible, draw both.

The highly reactive triple bond of benzyne is a powerful dienophile. Predict the productof the Diels–Alder reaction of benzyne (from chlorobenzene and NaOH, heated) withcyclopentadiene.

Following is an example of a type of reaction known as a Diels-Alder reaction 1,3-Pentadiene Ethylene 3-Methylcyclohexene (a racemic mixture) The Diels-Alder reaction between a diene and an alkene is quite remarkable in that it is one of the few ways that chemists have to form two new carbon-carbon bonds in a single reaction. Given what you know about the relative strengths of carbon-carbon sigma and pi bonds, would you predict the Diels-Alder reaction to be exothermic or endothermic? Explain your reasoning.