|M.Sc Student||Petrova Faina|
|Subject||Towards Cyclic C6|
|Department||Department of Chemistry||Supervisor||Professor Amnon Stanger|
|Full Thesis text|
A huge amount of studies have been dedicated to carbon allotropes, studying their dimensions and structures, efficient synthesis, as well as their properties and applications in research areas such as materials science or biomedicine. However, the knowledge of the mechanisms of the formation these allotropes is in its infancy and is based mostly on the theoretical studies and educated guesses. In order to have a better understanding of the formation processes of the carbon allotropes, to study the factors influencing their formation and to get ability to control their reactions, cyclic C6 molecule may be used. This molecule is the smallest sub-unit in the structure of most carbon allotropes. It is thus of a great interest to study the role of such species as intermediates in the formation of carbon materials.
As a general strategy, we planned to obtain the cyclic C6 by photolyzing hexaoxotricyclobutabenzene. We focused our study on the new efficient synthesis of hexaoxotricyclobutabenzene. We proposed two strategies for its preparation: (a) multiple oxidations of the bromides on the hexabromotricyclobutabenzene; (b) [2?] intramolecular ring closure of hexaoxocyclododecatriyne.
To use effectively the first strategy, a new approach for the oxidation of bromocyclobutabenzene was necessary. To overcome the instability of hexabromotricyclobutabenzene under radical reactions conditions, a primary research on the model system was conducted. The transformation of Br via two synthetic steps to OH followed by Swern oxidation proved to be the most promising one. Hopefully, this methodology will allow the efficient transformation of hexabromotricyclobutabenzene to hexaoxotricyclobutabenzene.
The synthesis of hexaoxocyclododecatriyne was attempted (strategy b). Three synthetic approaches were tested: (1) the direct synthesis; (2) cyclization of building blocks; (3) cyclization of dicarbonyl-protected building blocks. The study shows that the building blocks strategies are the most promising directions for the synthesis of hexaoxocyclododecatriyne.