Chapter 17.7, Problem 16ATS

Interpretation Introduction

Interpretation:

For the given transformation, the mechanism should be determined.

Concept introduction:

• Cycloaddition reaction is a concerted addition reaction of two reactants to form a ring; in which two π-bonds are converted to two σ-bonds.
• Diels-Alder reaction is a $\left[\text{4+2}\right]\text{ cycloaddition}$ reaction, in which a π-system having four atoms (diene) and a π-system having two atoms (dienophile) are undergoing in cycloaddition reaction and producing a substituted cyclohexene.
• Intra-molecular Diels-Alder reaction is possible, when the diene and dienophile are situated in a single compound.
• The mechanism of the ring formation in the Diels-Alder reaction is drawn by using three arrows representing the shifting of π-bonds in the two π-systems in a clockwise or counter clockwise fashion, so that the ring formation will take place.
• If the dienophile is a trans-alkene, then the product will be trans-product.

To determine: the mechanism for the given transformation reaction.