New methods for light-mediated carbon-heteroatom cross-couplings

Abstract

The selective formation of carbon-heteroatom bonds is important in synthetic organic chemistry due to the presence of heteroatoms in multiple natural products and active pharmaceutical ingredients. Over the last decade, photocatalysis has become a powerful toolfor the formation and cleavage of bonds in synthetic chemistry. Carbon–carbon and carbon–heteroatom bond forming reactions that traditionally required rare and sophisticated palladium catalysts can be carried out using nickel catalysis in combination with visible-light photocatalysis under mild conditions. Key to the success of this strategy is the ability of the photocatalyst (PC) to engage in energy or electron transfer events that activate thermodynamically stable Ni(II) intermediates and induce reductive elimination of the desired products. Still, the need of a dedicated photocatalyst based on noble metals, such as iridium- or ruthenium-polypyridyl complexes, represents a major drawback that results in high costs, tedious purification procedures, and renders the sustainability of these reactions low.