The Photocycloaddition of N -Vinylcarbazole with 3-Cyanostyrene
1987; Oxford University Press; Volume: 60; Issue: 8 Linguagem: Inglês
10.1246/bcsj.60.2899
ISSN1348-0634
AutoresAkira Tsuchida, Masahide Yamamoto, Yasunori Nishijima,
Tópico(s)Oxidative Organic Chemistry Reactions
ResumoAbstract The photocycloaddition reaction of N-vinylcarbazole (VCZ) as an electron donor, with 3-cyanostyrene as an electron acceptor, was studied. In nonpolar solvents, two cyclobutanes of cis-1-(9-carbazolyl)-2-(3-cyanophenyl)cyclobutane and trans-1-(9-carbazolyl)-2-(3-cyanophenyl)cyclobutane (in a ratio of 3 : 1) were obtained from an exciplex intermediate. The structure of cis cyclobutane seemed to originate from a sandwich conformation of the exciplex. In polar solvents, a photodissociation to free ion radicals was observed and trans-1,2-di(9-carbazolyl)cyclobutane was produced efficiently by means of a chain mechanism via a cation radical of VCZ. Transient intermediates were measured by means of nanosecond laser photolysis; the results supported the reaction scheme.
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