Synthesis of novel polycyclic aromatics and heteroaromatics via cascade cyclizations of enyne-allenes and enyne-isocyanates
Date of Graduation
Chambers College of Business and Economics
Kung K Wang
Studies on the thermal cyclization of enyne-isocyanates led to a new synthetic pathway to synthesize heterocycles. It was found that the enyne-isocyanates underwent predominantly C2--C7 cyclization at high temperature and the cycloaromatization was facilitated by the addition of silyl chloride.;The C2--C6 Schmittel cyclization of benzannulated enyne-allenes can provide efficient synthetic pathway for the polycyclic aromatics. As a result, new synthetic pathways to synthesize the 1,2-bis[5-(11 H-benzo[b]fluorenyl)]benzenes and related compounds were developed by employing the Schmittel cyclization reaction. The nonbonded steric interaction led to the formation of syn-isomers as major products, which hold potential to complex with transition metals to catalyze the olefin polymerization. Furthermore, another synthetic pathway to 2-(5-benzo[b]fluorenyl)-2'-hydroxy-1,1'-binaphthyl and related compounds was also successfully developed by using BINOL as starting material. Several enantiomerically pure syn atropisomers, which hold potential as hetero-bi-dentate ligands for asymmetric catalysis, were prepared.;Moreover, a simple and efficient pathway involving the Schmittel cyclization reaction was developed to synthesize novel polycyclic aromatics having a 54-carbon framework represented on the surface of C60. They could serve as potential precursors for a novel buckybasket.*.;*This dissertation is a compound document (contains both a paper copy and a CD as part of the dissertation). The CD requires the following system requirements: Adobe Acrobat.
Yang, Hua, "Synthesis of novel polycyclic aromatics and heteroaromatics via cascade cyclizations of enyne-allenes and enyne-isocyanates" (2006). Graduate Theses, Dissertations, and Problem Reports. 4282.