Photochemical Reactions of N-Methyl-1,2-naphthalenedicarboximide with Alkenes. Preferential Naphthazepinedione Formation

Article abstract of DOI:10.1246/bcsj.59.191

Irradiation of benzene solutions of N-methyl-1,2-naphthalenedicarboximide (1) in the presence of alkenes (2a,b,d-i) gave two regio-isomers of naphthazepinediones (3a,b,d-i and 4a,b,d-i).Stereospecificity of the naphthazepinedione formation was observed in the reaction with cis- and trans-2-butene (2a and 2b).Naphthazepinediones (3j and 4j) produced by the irradiation of 1 with ethyl vinyl ether (2j) underwent secondary photoreactions to give 7 and 8, respectively.On the other hand, irradiation of 1 with 2,3-dimethyl-2-butene (2k) resulted in the formation of oxetanes (13a,b) and 1:1-adducts of 1 and 2k at the carbonyl groups of 1 (14 and 15,ab).Irradiation of 1 with cis-stilbene (2l) afforded oxetanes (22a,b) and fragmentation products of oxetanes (23a,b, and 24).Stern-Volmer slopes (k_qτ) obtained from quenching of fluorescence of 1 by alkenes (2a-e,k) correlated to some extent with relative rates for disappearance of 1 in the reaction.Preferential formation of the naphthazepinedione was rationalized by the nature of the excited singlet state of 1 compared with those of other N-methylarenedicarboximides.