Chemoselective Transformation of Amphoteric Aziridine Aldehydes and Alpha-Boryl Aldehydes

The development of novel chemical strategies aimed at the synthesis of complex chemical entities comprises a central part of organic chemistry. An important area of this research is the development of reagents and/or building blocks that possess multiple handles with orthogonal reactivity. In this area, amphoteric molecules represent a platform for uncovering novel transformations previously inaccessible with conventional reagents. This thesis reports on the development of chemoselective transformations with amphoteric molecules developed in the Yudin lab. Following the introduction, Chapter 2 describes the development of an aldehyde-amine-alkyne (A3-coupling) reaction. Chapter 3 describes the development of an alkyl-MIDA boronate Suzuki-Miyaura cross-coupling reaction with direct application to the introduction of heterocycles to aryl substrates. The remainder of the thesis concentrates on amphoteric boryl aldehydes and the identification of unusual boron-containing products and intermediates. Chapter 4 describes a method for the synthesis of cyclic-amino boronates and highlights the influence of the MIDA boronate substituent on C-H activation. Chapter 5 delves into the chemoselective enolization of aldehydes to form a C,O-bis enolate. This intermediate was subsequently utilized in a Tsuji-Trost allylic alkylation reaction affording quaternary alkyl boronate products. Finally, Chapter 6 describes the condensation of aldehydes with amines, yielding enamines and enamides. These densely functionalized nitrogen-containing substrates were then applied to the synthesis of boron-containing heterocycles and other biologically relevant products.Ph.D.2016-11-30 00:00:0