Copper Carbazolides in Photoinduced C–N Couplings

Citation

Ahn, Jun Myun (2018) Copper Carbazolides in Photoinduced C–N Couplings. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/H8AP-G249. https://resolver.caltech.edu/CaltechTHESIS:05282018-184138570

Abstract

Photoinduced, copper-catalyzed reactions of organohalides have emerged in recent years as a powerful tool to construct a wide array of C–N bonds, which are prevalent in organic materials and polymers, pharmaceuticals, natural products, and ligands in transition metal catalysts. Described herein is the study and applications of copper complexes ligated by carbazole and its derivatives in photoinduced, copper-catalyzed C–N bond-constructing transformations. Various areas of synthetic inorganic and organic chemistry are explored, including in-depth mechanistic elucidation, ligand and catalyst design, reaction development, as well as spectroscopic and structural characterization of reactive copper complexes. Chapter 2 describes the mechanistic investigation on photoinduced, copper-catalyzed couplings of carbazoles with unactivated alkyl halides. A wide array of mechanistic tools suggests the viability of an out-of-cage C(sp³)–N coupling pathway. Spectroscopic and structural characterization data of the key intermediates are detailed. Chapter 3 outlines the design and preparation of a new copper-based photoredox catalyst supported by a tridentate bis(phosphino)carbazole ligands. The ground- and excited-state properties of the new photocatalyst are examined. Chapter 4 details the development of photoinduced, copper-catalyzed C(sp³)–N couplings of carbamates with unactivated alkyl bromides using the new copper photoredox system. The scope with respect to the nucleophile and the electrophile and mechanistic investigations are communicated. Chapter 5 illustrates the chemistry of copper complexes supported by bidentate (phosphino)carbazole ligands. A diverse array of copper complexes in both the S = 0 and S = 1/2 states are reported, including a rare, paramagnetic copper–phosphine complex that may serve as a structural model for key copper intermediates of the enantioselective C(sp³)–N couplings of carbazoles.

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