Date of Graduation
Eberly College of Arts and Sciences
Kung K Wang
A synthetic pathway was developed for the preparation of a precursor of a cycloparaphenylene derivative, which represents the shortest repeating carbon nanohoop segment of an armchair (6,6) carbon nanotube. As a key intermediate of the synthetic sequence, trans,trans-1,4-di(4-bromophenyl)-1,3-butadiene was synthesized by using the Homer-Wadsworth-Emmons reaction between 4-bromocinnamaldehyde and diethyl 4-bromobenzylphosphonate reported in the literature. The use of BF3˙OEt2 as a Lewis acid for the Lewis acid-catalyzed Diels-Alder reaction between trans,trans-1 ,4- di(4-bromophenyl)-1,3-butadiene and 1,4-benzoquinone was successful in producing cis-5,8-di(4-bromophenyl)-5,8-dihydro-1 ,4-naphthalenediol. The Diels-Alder reaction ensures that the two 4-bromophenyl substituents are cis to each other in the sixmembered ring, which is of critical importance for the subsequent dimerization reaction. Methylation with dimethyl sulfate in the presence of potassium carbonate afforded the corresponding methylated hydroquinone. The nickel(O)-catalyzed homocoupling reactions produced the corresponding dimers as a mixture of diastereomers with the two 1,4-dimethoxyphenyl groups pointing either in the same direction or in the opposite directions. It is envisioned that aromatization of the dimers could then lead to the cycloparaphenylene derivative.
Huang, Yiwei, "Development of Synthetic Pathways for Carbon Nanohoops" (2013). Graduate Theses, Dissertations, and Problem Reports. 4973.