ABSTRACT
Photocycloaddition of alkenes to aromatic rings is an important method for chemical conversion and construction of polycyclic compounds. In comparison with photocycloaddition of two alkenes and that of enone with alkenes, mild and chemoselective excitation by light is possible because aromatic rings oen have absorption bands in longer wavelengths. In addition, most of them proceed via structurally controlled exciplexes consisting of aromatic rings with alkenes.1 erefore, highly selective photocycloaddition can be designed by control of structure and reactivity of substrates and exciplexes, although there are several modes in photocycloaddition of aromatic rings with alkenes, these are [2 + 2], [3 + 2], [4 + 2], [4 + 4], and so on.
