Photocatalytic C(sp³)-H bond functionalization by Cu(I) halide cluster-mediated O₂ activation

Area of Science:

• Organic Chemistry
• Photocatalysis
• Catalysis

Background:

• Selective functionalization of C(sp³)-H bonds with dioxygen remains a significant challenge in organic chemistry.
• Mild reaction conditions are desired for sustainable chemical synthesis.

Purpose of the Study:

• To develop a novel photocatalytic system for selective C(sp³)-H bond functionalization using dioxygen.
• To explore the mechanism of photoinduced single-electron transfer (SET) processes involving copper clusters and oxygen.

Main Methods:

• Utilizing photoactive copper(I)-halide(X) (X = Cl, Br, I) clusters as catalysts.
• Employing light irradiation to initiate photocatalysis.
• Investigating the reaction mechanism through proposed SET pathways.

Main Results:

• Achieved selective monooxygenation and C-C oxidative cross-coupling of C(sp³)-H bonds.
• Demonstrated effective catalysis using unreactive O₂ under mild conditions.
• Proposed a mechanism involving photoinduced SET between Cu(I)-clusters and O₂, forming reactive intermediates.

Conclusions:

• The developed protocol advances copper(I)-cluster mediated photoredox catalysis.
• Offers a new pathway for synthesizing functional fine chemicals with high selectivity.
• Highlights the potential of merging transition metal and photocatalysis for challenging transformations.