Date of Graduation
Eberly College of Arts and Sciences
Kung K. Wang.
A synthetic sequence was developed for the preparation of a diindeno-fused 4Hcyclopenta[def] phenanthrene derivative containing two bromo substituents as a potential building block for the construction of macrocyclic acetylenes. The synthetic sequence required the preparation of a benzannulated enediyne, 1-bromo-2-ethynyl-3-(2- phenylethynyl)benzene. The Sonogashira reaction between 1,3-dibromo-2-iodobenzene and (trimethylsilyl)ethyne produced I ,3-dibromo-2-[(trimethylsilyl)ethynyl]benzene. Metalhalogen exchange with n-butyllithium followed by iodination with iodine furnished 1-bromo- 3-iodo-2-[(trimethylsilyl)ethynyl]benzene. A second Sonogashira reaction with phenylethyne followed by desilylation then furnished 1-bromo-2-ethynyl-3-(2-phenylethynyl)benzene.;Treatment of an excess of 1-bromo-2-ethynyl-3-(2-phenylethynyl)benzene with lithium diisopropylamide followed by condensation with 2,2-dimethoxy-1 ,3-indandione furnished the corresponding propargylic diol as the major adduct and the corresponding mono-ol as the minor adduct. On exposure to thionyl chloride, the diol underwent a Schmittel cascade cyclization reaction to produce the diindeno-fused 4H-cyclopenta[def]phenanthrene derivative containing two bromo substituents. The presence of the two bromo substituents provides handles for additional Sonogashira reactions for the construction of macrocyclic acetylenes.
Tseng, Chi-Yuan, "Development of Synthetic Pathways for Macrocyclic Acetylenes" (2013). Graduate Theses, Dissertations, and Problem Reports. 3623.