Synthesis of Polycyclic Compounds by Using Photocycloaddition Reactions to Aromatic Rings

Synthesis of polycyclic compounds by using inter-and intramolecular photocycloaddition reactions of aromatic rings with unsaturated components was investigated. Intramolecular [3+2]photocycloaddition of alkenylnaphthalenes gave triquinane compounds in high yields. Photospirocyclization also took place from alkenylnaphthalenes. Photocycloaddition of alkynylnaphthalenes gave other kinds of triquinane compounds. Novel eight-membered ring compounds were formed in intramolecular photocycloaddition of alkenylphenanthrenes. Inter-and intramolecular photocycloaddition reactions of alkenes to pyrene and chrysene were also developed. When cyclopropane derivatives were used, processes of [3+2] photocycloaddition and photoalkylation were observed. Hydrogen bonding interactions can be used for development of regio-and stereoselective photocycloaddition reactions. Singlet exciplexes are served as reactive intermediates in these photocycloaddition reactions.