APPLICATIONS OF PHOTOREDOX-CATALYZED REVERSIBLE C–H BOND CLEAVAGE AND FORMATION

Abstract

In the past decade, photoredox catalysis has emerged as a highly enabling and widely adopted catalytic platform in the field of organic synthesis. The ability of photoredox catalysts to selectively activate organic substrates via single electron transfer pathways to generate reactive open-shell radical species under mild conditions has led to the development of a diverse array of novel synthetic transformations, enabling previously elusive bond disconnections that can simplify and streamline the synthesis of molecules. While the application of photoredox strategies for bond formation has been, and continues to be, intensely studied, their potential as a platform for the reversible cleavage and formation of C–H bonds remains largely untapped.

This dissertation describes research efforts towards the application of photoredox catalysis in the development of methods to reversibly cleave and form C–H bonds for two different applications. Firstly, Chapter 2 describes the utilization of a photoredox and hydrogen atom transfer-catalyzed manifold to harness in situ generated α-amino radicals for the development of a novel method for the isotopic labeling of pharmaceutical drugs. Chapter 3 then goes on to describe how the photoredox-catalyzed generation of prochiral radicals can be exploited as a racemization platform to facilitate the racemization of traditionally inert stereocenters. This newly developed racemization protocol is then applied in conjunction with biocatalytic kinetic resolutions for the discovery of new and unprecedented stereoconvergent reactions.