The photocycloaddition of isocarbostyril to olefins

✍ Scribed by George R. Evanega; Diane L. Fabiny

• Publisher: Elsevier Science
• Year: 1971
• Tongue: French
• Weight: 224 KB
• Volume: 12
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(01)87451-7

✦ Synopsis

Recently we reportedla that the photochemical cycloaddition of carbostyrils to olefins formed I:1 wdducts in e. regiaspecific manner (only head-ta-teil edducts were ahtatned).

We would now like to describe some photocycloadditions of isocarbostyril to olefins to give 1:l adducts. Isobutylene, tetrsmethylethylene and cyclopentene react with 1, in a manner similar to carbostyril. However, l,l-dichloroethylene gives a mixture of head-to-tail and hea&&o:neab isomers +if.n isoc&oo&vrY&, 'otit osQ,y 'tie 'neaa-'r.o&aTl Lsomer w%n ca*ooSxvrYl. Furthermore, isocarbostyril reacts much less efficiently than carbostyril in both dimerisation ancb qv&oahhition reactions tiYn 0ieBns in 'Kne_nresence anh ansence oZ 'tie sensYz%zers in-vesX~a%&. A 700 ml ethanol solution of isocarbostyril (b 7.25 g, 0.050 M) and tetrsmethylethylene (42 g, 0.50 M) was purged with N2 and then irradiated for 9 days in a quartz vessel in a Rayonet Photochemical reactor equipped with 3500 i Hg vapor black light fluorescent lamps. The prohucts2 o%x&neh were .62 g 10.@!$ ,2 ma ID.33 Ip*> 33; for _2? 4~ 3Dl-Y J~~~HQ~J~:YLXZI: '*