Enantioselective Intramolecular Aromatic [4 + 4] Photocycloaddition in Crystalline State:  Parameters for Reactivity

Photoreactivity of seven 9-anthryl-N-(naphthylcarbonyl)carboxamide derivatives, 1a−g, in their intramolecular [4 + 4] photocycloadditions in solid state is discussed on the basis of their single-crystal X-ray analyses. The distances (d₁ and d₂) between the two carbon atoms to be reacted, the angles (θ₁ and θ₂), and the torsion angle (θ₃) between the anthracene and naphthalene rings were chosen as structural parameters for reactivity. For 1a and 1e, the first example of absolute asymmetric synthesis in [4 + 4] photocycloaddition was attained.