Photochemical Cycloaddition of Phenanthrene-Fused Lactones to (E)-Anethole. Structural Effects and Dual Collapse Processes of an Exciplex Leading to Cycloadducts.
Structural Effects on Photochemical Intermolecular Cycloaddition of Phenanthrenecarboxylic Lactones. Dual Collapse Processes of an Exciplex Leading to Cycloadducts
irradiation with (E)-anethole in benzene 10-hydroxymethyl-9-phenanthrenecarboxylic lactone (STL) gave an intermolecular [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