Chapter 27, Problem 27.15P

(a) Draw the product of the following $\left[4+2\right]$ cycloaddition, which was carried out in the early stages of the synthesis of the alkaloid reserpine (Problem 22.83). Indicate the stereochemistry at any newly formed stereogenic centers. (b) Draw the $p$ orbitals of the alkene and the terminal carbons of the conjugated diene, and show how the orientation of the reactants and orbital overlap lead to the observed stereochemistry.