Title

Expanding the Scope and Utility of the Scientific Microwave Apparatus in Organic Synthesis: Reactive Gases, Scale-Up and New Methodology Development

Date of Completion

January 2010

Keywords

Chemistry, General|Chemistry, Organic

Degree

Ph.D.

Abstract

Microwave heating has seen increasing use in synthetic organic chemistry ever since the first published results using domestic microwave ovens in 1986. Commercially available scientific microwave reactors offer increased reproducibility and safety for chemical reactions. This dissertation covers a variety of methods developed using state-of-the-art scientific microwave reactors. Phenols are prepared from aryl halides in high-temperature to near-critical water. In the sealed vessel of the microwave reactor, reactive gases can be introduced in a facile manner. Carbon monoxide is incorporated into aryl carboxylic acids or esters via a palladium-catalyzed transformation of iodoarenes in water or simple alcohol solvents. Ethylene can be exploited to produce unsymmetrically-substituted stilbenes via a two-step, one-pot palladium-catalyzed Heck coupling with two iodo- or bromoarenes. In combination with an electrodeless discharge lamp activated by the microwave field, oxygen is used as the terminal oxidant in the transformation of 1,4-dihydropyridines into pyridines. Finally, the scalability of microwave-heated methods is tested, including the use of a prototype batch reactor capable of heating up to 12 L reaction volume. ^