Date of Award

2013

Degree Type

Thesis

Degree Name

Master of Science in Chemistry

Department

Chemistry

First Advisor

Brenton DeBoef

Abstract

Biaryl bonds are a common motif found in biologically active compounds and the majority of marketed pharmaceuticals. The contemporary methods used to synthesize these biaryl bonds, albeit high yielding, are not economical because they require several prefunctionalization steps that create a high volume of waste and byproducts. Cross-dehydrogenative coupling (CDC) is the future of green coupling techniques, since it requires no prefunctionalization of substrates and can obtain high yields with a relatively low catalyst loading. Herein, we report on advances being made in the field of CDC, and our own efforts to achieve cross coupling utilizing benzimidazole moieties.

The first manuscript, “Aryl-Aryl Bond Formation via CDC Reactions” is a comprehensive review of the latest and most notable achievements being made in the area of biaryl CDC reactions. The manuscript focuses on cross-dehydrogenative coupling as a green method that can be used to create aryl-aryl bonds on a vast array of substrates. Several different classes of CDC reaction conditions were examined including Pd, Rh, Ru, Cu, and Fe-based catalytic systems.

The second manuscript, “Intramolecular Arylation of Benzimidazoles via Pd(II)/Cu(I) catalyzed Cross-Dehydrogenative Coupling” describes research done on the intramolecular biaryl CDC reaction between simple arenes and benzimidazoles. This novel reaction is carried out on N-benzylbenzimidazoles that upon cyclization forms a fused polycyclic system. The reaction conditions were optimized and tested on a large library of substrates, and the mechanism was probed using kinetic isotope studies and varied reaction conditions to suggest a unique Pd(II)/Cu(I) catalytic cycle.

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