Photocatalytic C(sp3)–C(sp3) cross-coupling of carboxylic acids and alkyl halides using a nickel complex and carbon nitride

Developing robust and reliable methods for constructing C(sp3)–C(sp3) bonds is critically important for synthesizing a diverse array of functionalized drug molecules. However, this reaction poses significant challenges from a chemical standpoint due to issues with selective activation and regioselectivity, functional group compatibility, complex catalyst design, and slow reaction kinetics. Current metallaphotoredox approaches do not provide a viable solution because they rely on expensive, toxic, and rare iridium photocatalysts, severely limiting their widespread application. In this study, we introduce carbon nitride nanosheets (nC3N4) as an efficient and sustainable alternative to traditional iridium-based catalysts. When combined with nickel catalysis, nC3N4 facilitates the cross-coupling of aryl halides and carboxylic acids. Our results demonstrate a broad substrate scope, including various aryl halides and carboxylic acids, and highlight the recyclability of the photocatalyst. Density functional theory calculations provide molecular insights into the role of nickel single atoms in facilitating photodecarboxylation and subsequent C–C bond formation. This work significantly expands the potential of photoredox chemistry, and offers a novel method for efficient, industrially relevant light-to-chemical conversion processes.