69212-03-9Relevant academic research and scientific papers
The differing mechanisms of photo-formation of 7-cyanobenzocyclooctatetraene from 7- and 6-cyano-2,3-benzobicyclo[4.2.0]octa-2,4,7-triene
Bender, Christopher Owen,Dolman, Douglas,Foesier, Jeremy Christian,Lawson, Sherry Lee,Preuss, Kathryn Elvia
, p. 37 - 44 (2003)
It is known that 7-cyanobenzocyclooctatetraene (COT 2) is a product of the thermolysis and direct photolysis of 7- and 6-cyano-2,3-benzobicyclo[4.2.0]octa-2,4,7-triene (1 and 5), though the mechanisms of these rearrangements have not been reported. In the present study experiments have been carried out using the deuterium-labelled trienes 1a (93%-d1 at C-6) and 5a (93%-d1 at C-8), which were formed from 2π + 2π photo-closure (direct irradiation) of COT 2a labelled at C-8. The results reveal that whereas the thermolysis of 1a and 5a and the direct irradiation of 5a reform COT 2a, probably via cleavage of the strained cyclobutene C-1-C-6 bond, the direct irradiation of triene 1a gives a differently labelled COT product, containing the deuterium exclusively at C-9. The mechanism proposed for the latter phototransformation is a modification of the Zimmerman di-π-methane rearrangement.
