Chapter 27, Problem 27.56P

Interpretation Introduction

Interpretation: The formation of F from E by a two step reaction sequence consisting of a $\left[1,5\right]$ sigmatropic rearrangement followed by a $\left[4+2\right]$ cycloaddition is to be shown by using curved arrows.

Concept introduction: In the sigmatropic rearrangement, the rearrangement of pi bond and the breaking of sigma bond take place. This results in the generation of new sigma bond in the product. In this type of rearrangement, the number of pi bonds remains constant in the reactant as well as in the product.

Curved arrows aid in determining the movement and flow of electrons in the reaction. The electrons that take part in the chemical reactions are shown by the curved arrows.