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Benzylic C-H Esterification with Limiting C-H Substrate Enabled by Photochemical Redox Buffering of the Cu Catalyst.

Dung L GoldenChaofeng ZhangSi-Jie ChenAristidis VasilopoulosIlia A GuizeiShannon S Stahl
Published in: Journal of the American Chemical Society (2023)
Copper-catalyzed radical-relay reactions provide a versatile strategy for selective C-H functionalization; however, reactions with peroxide-based oxidants often require excess C-H substrate. Here, we report a photochemical strategy to overcome this limitation by using a Cu/2,2'-biquinoline catalyst that supports benzylic C-H esterification with limiting C-H substrate. Mechanistic studies indicate that blue-light irradiation promotes carboxylate-to-copper charge transfer, reducing resting-state Cu II to Cu I , which activates the peroxide to generate an alkoxyl radical hydrogen-atom-transfer species. This "photochemical redox buffering" introduces a unique strategy to sustain the activity of Cu catalysts in radical-relay reactions.
Keyphrases
  • metal organic framework
  • resting state
  • functional connectivity
  • aqueous solution
  • highly efficient
  • reduced graphene oxide
  • room temperature
  • electron transfer
  • walled carbon nanotubes