Development of Metal-Catalyzed and Photochemical Approaches to Carbon-Carbon Bond Forming Reactions

The development of methods to construct carbon-carbon bonds is fundamental to synthetic organic chemistry. This transformation provides access to a variety of organic compounds including medicinal and pharmaceutical agents, agrochemicals, and polymers. There is a growing interest in practical and efficient catalytic approaches to construct carbon-carbon bonds allowing access to valuable organic molecules. This manuscript describes a review of catalytic methods for onium ylide rearrangements in aromatic systems, our studies on catalyst-controlled rearrangements of onium ylides in indole systems, and our approaches toward photocatalytic asymmetric coupling of imines and alkylarenes. In the first chapter, an overview of the known synthetic approaches for metal-catalyzed onium ylide rearrangements in aromatic systems is discussed. Various catalytic examples from the recent literature show onium ylides undergoing dearomative [2,3]-rearrangement to give alkylated aromatic compounds as final products. The influence of substrate and solvent effects in the selectivity of rearrangements has been demonstrated through several examples. The second chapter describes our studies in the development of catalytic rearrangements of indole-based onium ylides. Our approach allows regiodivergent rearrangements of oxonium ylides in a catalyst-controlled manner to access substituted indole compounds. This method shows the impact of transition-metal catalysis in governing the selectivity of chemical transformations. We also present various experimental and theoretical studies to analyze the mechanistic pathways involved in the methodology. The development of the methodology has also allowed further functionalization of the products resulting in the total synthesis and structural revision of an indole alkaloid. In the third chapter, we describe our approaches in exploiting photocatalysis to perform the functionalization of feedstock chemicals to access enantioenriched chiral amines. Our synthetic strategy leverages the known photophysical properties of compounds to rationally design and develop a catalytic transformation in an enantioselective fashion. The challenges associated with realizing this transformation and our approaches to solving them are discussed.