Structural Effects on Photochemical Intermolecular Cycloaddition of Phenanthrenecarboxylic Lactones. Dual Collapse Processes of an Exciplex Leading to Cycloadducts

Article abstract of DOI:10.1246/cl.1991.1683

On irradiation with (E)-anethole in benzene 10-hydroxymethyl-9-phenanthrenecarboxylic lactone (STL) gave an intramolecular <2+2> cycloadduct, a cyclobutane derivative, while 8-hydroxymethyl-9-phenanthrenecarboxylic lactone (SCL) afforded both of a cyclobutane with the same conformation and an olefinic product derived from an oxetane precursor, the carbonyl adduct.The formation of cycloadducts of highly different structures in SCL was ascribed to competitive collapse of the involved exciplex to the products.