Synthesis of Helical and Bowl-Shaped Polycyclic Aromatic Compounds via Benzannulated Enyne-Allenes
Date of Graduation
Eberly College of Arts and Sciences
Kung K Wang
The cascade radical cyclization of the benzannulated enyne-allenes provides an efficient synthetic pathway to a variety of polycyclic aromatic hydrocarbons. Three indeno-fused 4,5-diheteroarylphenanthrenes were synthesized by thermolysis of corresponding benzannulated enyne-allenes. Its X-ray structure shows that the substituents at C4 and C5 positions of the phenanthryl system are essentially parallel to each other and cause severe helical twist of the structures. The presence of two terpyridyl units in 2.2c allowed it to be used as a ligand for the synthesis of dinuclear ruthenium(II) bis(terpyridine) complexes possessing severe helical twists.;Several 1,4-naphthoquinone methides were synthesized via an unusual acid-catalyzed cascade cyclization sequence followed by two-carbon ring expansion of benzannulated enediynyl alcohols. The simplicity of the synthetic sequence and the mildness of the reaction condition make this pathway especially attractive.;A new synthetic route to a bowl-shaped aromatic hydrocarbon 4.87 was developed. The key steps of this efficient pathway include a cascade cyclization of the corresponding enyne-allene and subsequent palladium-catalyzed intramolecular arylation reactions of the aromatic dibromides. Sever attempts were made to synthesize a precursor of buckybowl 4.54. The suitable precursor will bear a framework of 4.54 and could be fully aromatized to form 4.54. Further exploration is required to overcome difficulties encountered toward the synthesis of buckybowl 4.54.
Wen, Bo, "Synthesis of Helical and Bowl-Shaped Polycyclic Aromatic Compounds via Benzannulated Enyne-Allenes" (2010). Graduate Theses, Dissertations, and Problem Reports. 4671.