Diels‐Alder Adducts of Benzene with Arenes and Their [4+2] Cycloreversion

Abstract

The retrocleavage of the adducts 1–5 proceeds according to a synchronous mechanism. The resonance energy gain in the products is 11 to 40 kcal/mol; in each case, 40% of this gain is reflected in a reduction of the energy of the transition state.