Chemistry of anti-o,o‘-Dibenzene

• Published in: Journal of the American Chemical Society 1997-08, Vol.119 (32), p.7470-7482
• Main Authors: Noh, Taehee, Gan, Hong, Halfon, Sharon, Hrnjez, Bruce J, Yang, Nien-chu C
• Format: Article
• Language: English
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja970199o

A new and efficient preparation of anti-o,o‘-dibenzene 1 has been achieved in three steps from cis-3,5-cyclohexadiene-1,2-diol 25. Utilizing a method for deoxygenation of 1,2-diols developed in our laboratory, anti-tetraol 23 was converted to 1 in 65% yield on a 0.5 g scale. This has allowed us to explore the chemistry of anti-dibenzenes extensively. The kinetics for thermal reversion of 1 to benzene have been studied in three different solvents. The direct photolysis of 1 to benzene has been found to form excited benzene in unit efficiency. This high efficiency of adiabatic photon up-conversion in the singlet manifold is unprecedented. No light was detected in the thermal dissociation of 1 in solution using various sensitizers. The chemiluminescence spectrum from the thermolysis of 1 in the presence of perylene has been recorded and found to correspond to the emission of perylene excimer. Although the efficiency of the chemiluminescent process was very low, it has proven to be one of a very few examples of chemiluminescent reactions from pure hydrocarbons. The possible mechanisms were discussed. Benzene 1,4-endoperoxide 36 was formed during the photolysis of monoperoxide 34 at low temperature. Peroxide 36 underwent a quantitative concerted retrocycloaddition to benzene and singlet oxygen. The half-life of 36 was determined to be 29 min at −30 °C.