Organic Chemistry: Concepts and Applications - Headley Allan D. 2020

An Overview of the Reactions of Organic Chemistry
6.8 Pericyclic Reactions

Pericyclic reactions are a lot different from the reactions discussed thus far. The reactants of pericyclic reactions are typically conjugated alkenes, and throughout the course of pericyclic reactions, the pi (π) electrons of the reactants are transformed to form new bonds. Typically, heat or light is required for pericyclic reactions. The most noted pericyclic reaction is given in Reaction (6-34) and is also known as the Diels—Alder reaction, named after the German chemists, Otto Diels and Kurt Alder, who discovered this reaction. They discovered the reaction in 1938 and received the Nobel Prize for their contribution to the advancement of chemistry in 1950. For the pericyclic reaction given in Reaction (6-34), arrows are used to show the movement of the pi (π) electrons to form new bonds of a six-member ring.

(6-34)πImage

Problem 6.11 is designed to help students recognize the reactants and to predict possible products for this type of pericyclic reactions based on your analysis of the above reaction.

Problem 6.11

Give the product for the following pericyclic reactions.

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Pericyclic reactions will be covered in a lot more detail in Chapter 18, but at this point, students should be able to identify the uniqueness of pericyclic reactions, compared to the other reactions covered thus far and the special feature of conjugated double bond requirement for these reactions.