An Investigation of Gold(I) Catalyzed Cycloaddition Reactions

Unit I, Two successful 13- and 15-membered macrocycles containing furan and α-chloroketone functional groups were synthesized. Macrocycles were subjected to solvent mixture (Et₃N, CF₃CH₂OH, and Et₂O), and an oxyallyl cation was presumably formed, which proceeded to react with the furan moiety to give transannular [4C+3C] cycloaddition products. In addition, the tricyclic ring system with an oxabicyclo-[3.2.1]octadiene and a fused 6-membered ring was produced efficiently using the readily available propargyl ester-furan substrate in the presence of a Au(I) complex. The reaction involves a tandem 3,3-rearrangement of the propargyl ester followed by an intramolecular [4C+3C] cycloaddition reaction. Unit II, With the use of benzonitrile-stabilized Au(I) catalyst [Au(IPr)(NCPh)]⁺SbF6^-, a spectrum of reactivity is observed upon reactions of propargyl esters with cyclic vinyl ethers, ranging from exclusive [3C+2C] cycloaddition reactions to exclusive cyclopropanation depending on the structure of the vinyl ether. Some cyclopropanation products rearrange into the corresponding [3C+2C] cycloaddition products after treatment with fresh Au(I) complex at 80°C. Vinylcyclopropanes formed from dihydrofuran and dihydropyran resisted such rearrangement, even in the presence of fresh Au(I) catalyst at elevated temperature. A dual pathway is proposed for the Au(I) catalyzed reactions between propargyl esters and cyclic vinyl ethers. In addition these cycloaddition reactions were attempted with chiral NHC Au(I) complexes and novel chiral ADC Au(I) complexes. The ADC Au(I) catalyzed cycloaddition reaction led to the discovery of a cascade reaction consisting of first: [3C+2C] cycloaddition between propargyl ester and vinyl ether followed by cyclopropanation of the enol ester double bond, in the [3C+2C] cycloadduct, with propargyl ester. These cascade products were found to be resistant to rearrangement of the cyclopropyl ring in the presence of fresh Au(I) catalysts at elevated temperatures. Unit III, A brief report on exploring the hydroamination reaction with O-benzylhydroxylamine and aryl acetylenes catalyzed by Au(I) complex [Au(IPr)(NCPh)]⁺SbF6^- yielding exclusively trans oximes under mild conditions.

Name thesis:degree_name

Doctor of Philosophy

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Chemistry and Biochemistry

Grantor dc:publisher

Miami University

Year dc:date

2013

Author dc:creator

• Conyers, Ryan C.

Contributors dc:contributor

• Gung, Benjamin
• Taylor, Richard

• Organic Chemistry
• Chemistry
• Gold
• Au
• cycloaddition
• macrocycle
• furan
• transannular
• intramolecular
• intermolecular
• cyclopropanation
• cascade
• cortistatin

Statement dc:rights

• unrestricted
• This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.

Language dc:language

English

Repository record dc:identifier

http://rave.ohiolink.edu/etdc/view?acc_num=miami1366197923

OAI identifier oai:identifier

oai:etd.ohiolink.edu:miami1366197923