Date of Award

2015

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Graduate Group

Chemistry

First Advisor

Marisa C. Kozlowski

Abstract

PART I. There are few reports on the synthesis of 2-aryl-2-nitroacetates, highlighting a need for development in this area. This section describes a high-throughput experimentation (HTE) approach to discover suitable conditions for the coupling of aryl bromides and α-nitroacetates to generate 2-aryl-2-nitroacetates. The best reaction conditions are 2.5 mol % Pd2dba3•CHCl3, 10 mol % t-BuXPhos, 1.2 equiv CsHCO3 in toluene at 75 °C, which afford products in isolated yields of 52–96%.

2-Aryl-2-nitroacetates are central precursors to other small molecules making them valuable building blocks in synthesis. Efficient methods were developed for the conversion of 2-aryl-2-nitroacetates to several product classes that are difficult to make: aryl nitromethanes (76–98% yield), α-keto esters (51–86% yield), and α-aryl α-amino acids (63–85% yield).

PART II. Small molecule organocatalytic anion-binding chemistry is in its early stages of development in the organic laboratory, and research in this field is important for its advancement. This section describes synthesis of a new class of anion-binding catalysts focused on a xanthene scaffold.

Over twenty potential catalysts were made and include three types: unsymmetrical catalysts, C2-symmetrical catalysts, and bifunctional catalysts. These compounds are better at promoting the Pictet-Spengler-type reaction previously reported by Jacobsen. Because of this fact the cyclization of 3- and 2-substituted furans into N-acyliminium ions was investigated. The top catalyst for 2-substituted furans is a bisamide xanthene compound (60% conversion), and the top catalyst for 3-substituted furans is a thiourea-amide xanthene compound (42% conversion, 24% ee).

PART III. The discovery of new materials is an exciting and important field of organic synthesis. A tetrachlorinated bisbenzo[a]phenazine was accessed in seven steps and 14% overall yield (99% ee). It has unique chromic properties that justify its application in functional materials. The color-changing transitions and the corresponding solid phases were studied using single crystal x-ray diffraction, powder x-ray diffraction, photo-image processing, and differential scanning calorimetry. These properties arise from two polymorphs and the ability of the phenazine to form weak OH•••Cl interactions.

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