55277-76-4Relevant academic research and scientific papers
Photochemistry of 4-Cyano-2,3-benzobicycloocta-2,4,7-triene
Bender, Christopher Owen,Dolman, Douglas,Tu, Noah
, p. 5015 - 5020 (2007/10/02)
4-Cyano-2,3-benzobicycloocta-2,4,7-triene (11) was found to be thermally and photochemically reactive.Heating solutions of 11 at 150 deg C for 2 h gave 5-cyanobenzocyclooctatetraene (10) quantitatively.The direct irradiation of triene 11 gave 2-cyanobenzosemibullvalene (i.e., SB 12, 63percent, Φ = 0.067), COT 10 (28percent, Φ = 0.031), and 1-cyanonaphthalene (ca. 0.5percent, Φ = 0.0005).Upon sensitization with p-(dimethylamino)benzophenone, 11 gave 12 (30percent, Φ = 0.028), COT 10 (9percent, Φ = 0.0093), and 1-cyanonaphthalene (2percent, Φ = 0.0018).Studies with deuterium-labeled triene (11a) revealed that semibullvalene produced from direct irradiation possessed a different label distribution to that obtained from sensitized irradiation, and hence state-dependent pathways operate in the SB formation.The mechanism proposed for the SB formation from S1 of 11 involves a 1,2-shift with cleavage of the cyclobutene C1-C6 bond of the triene, while SB formation from T1 results from a Zimmermann di-?-methane rearrangement.
The photochemistry of 1-cyano-2,3-benzobicycloocta-2,4,7-triene
Bender, Christopher Owen,Clyne, Dean Sutherland,Dolman, Douglas
, p. 70 - 76 (2007/10/02)
The title compound (10) was prepared, along with the 4-cyano-isomer (11), by the direct irradiation of 5-cyanobenzocyclooctatetraene (9); the yields were 82percent (Φ10 = 0.0030) and 12percent (Φ11 = 0.0004) respectively.Triene 10 was thermally and photochemically reactive.Heating solutions of 10 at 150 degC for 1 h gave COT 9 quantitatively.On direct irradiation 10 forms 5-cyanobenzosemibullvalene (12; 5percent, Φ = 0.019, COT 9 (70percent, Φ = 0.56), and 1-cyanonaphthalene (14percent, Φ = 0.078).Sensitized irradiation of 10 gave 9 exclusively (92percent, Φ = 0.88).COT 9 was also produced by the direct irradiation of semibullvalene 12 (75percent, Φ = 0.13).Studies with deuterium labelled 10 suggest that the photoformation of COT 9 involves a simple electrocyclic opening of the cyclobutene ring of the triene.Additionally, the labelling results indicate that the formation of semibullvalene 12 from 10 derives from the operation of two reaction pathways, the major one of which appears to be a Zimmerman di-?-methane rearrangement.The mechanism proposed for the minor pathway to 12 has not been observed in other bicyclooctatrienes. Key words: mechanisms, rearrangements, photochemistry, di-?-methane.
