Author

Lijun Chen

Date of Graduation

2015

Document Type

Thesis

Degree Type

MS

College

Eberly College of Arts and Sciences

Department

Chemistry

Committee Chair

Jessica Hoover

Committee Co-Chair

Brian Popp

Committee Member

Xiaodong Shi

Abstract

Metal-catalyzed cross-coupling reactions have become a powerful tool to construct unsymmetric biaryl structures. Traditional cross-coupling requires prefunctionalized coupling partners, resulting in poor atom- and step-economy. As an alternative, carboxylic acids are attractive coupling precursors after the release of carbon dioxide. Carboxylic acids are readily available in a wide scope and easily stored and handled. Over the past decade, work has been performed on developing new methods for metal catalyzed redox neutral decarboxylative coupling reactions with benzoic acids. However, redox neutral decarboxylative coupling reactions require a prefunctionalized aryl halide or aryl triflate coupling partner. Alternatively, oxidative decarboxylative cross-coupling enables direct C-H arylation, minimizing the possible halide waste. Current oxidative decarboxylative coupling systems suffer from few choices of metal catalyst and limitations of substrate scope. Because copper systems show a broad scope of both decarboxylation and C-H arylation reactions, copper salts might be potential for promoting oxidative decarboxylative cross-coupling reactions. During the past three years, I have been working on developing a new reaction of decarboxylative cross-coupling of arene C-H bonds with benzoic acids to construct biaryls using copper catalysts. Here in my thesis, I will report two classes of reactions I studied: (1) Copper-catalyzed reactions of 2-phenylpyridine and 2-nitrobenzoic acid; (2) Copper-catalyzed decarboxylative C-H arylation reactions of benzoxazoles with 2-nitrobenzoic acids.

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