A Novel Approach to Heterocycles via Photocycloaddition Reactions of Nitrogen-Containing Heteroaromatics

摘要

Photochemistry of aromatic compounds has received much attention from both the mechanistic and synthetic perspectives, and the intra- and intermolecular photochemical cycloaddition of carbon aromaics is well documented. Furthermore, the photocycloaddition to alkenes to benzene derivatives is also a useful method for synthesizing natural products. However, in contrast, the photocycloaddition reaction of aza-aromatics, such as pyridines, pyridazines, pyrazines, or pyrimidines, is an underdeveoped area of research. We found that the induction of suitable substituents to appropriate position of aza-aromatic ring made the photoreactivity considerably high. Many new photochemical reactions for pyridine derivatives have been found in photodimerization, photocycloaddition with alkenes, furan, benzofuran or cyanonaphthalene. These reactions provide not only new photochemical aspect of aza-aromatics, but also useful synthetic method of polycyclic heterocycles.