Novel Annelation Method to Pyridine and Isoquinoline by Photochemical Means

Abstract

Intramolecular photoaddition reactions of 2-(ω-alkenyl)isoquinolin-1(2H)-ones and 1-(ω-alkenyl)pyridin-2(1H)-ones were examined, and the regioselectivity and dependence of these reactions on the length of methylene chain in the alkenyl group were clarified. By utilizing these reactions, a synthetic route to indolizine and quinolizine derivatives was elaborated. By an extension of this approach to the intermolecular reaction, 6-methoxy-3-methyl-1, 2-dihydrocyclobuta[b]pyridin-4(3H)-one was synthesized from 4, 6-dimethoxy-1-methylpyridin-2(1H)-one.