Copper Catalyzed C(sp3)–H Bond Alkylation via Photoinduced Ligand-to-Metal Charge Transfer

• Published in: Journal of the American Chemical Society Vol. 143; no. 7; pp. 2729 - 2735
• Main Authors: Treacy, Sean M, Rovis, Tomislav
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 24.02.2021; Amer Chemical Soc
• Subjects: alkenes; Alkenes - chemistry; Alkylation; Carbon - chemistry; Catalysis; catalysts; Chemistry; Chemistry, Multidisciplinary; chlorine; Copper - chemistry; diastereoselectivity; hydrogen; Hydrogen - chemistry; Ligands; oxidants; Oxidation-Reduction; Physical Sciences; Quantum Theory; Science & Technology; Stereoisomerism
• ISSN: 0002-7863; 1520-5126; 1520-5126
• DOI: 10.1021/jacs.1c00687

Utilizing catalytic CuCl2 we report the functionalization of numerous feedstock chemicals via the coupling of unactivated C­(sp3)–H bonds with electron-deficient olefins. The active cuprate catalyst undergoes Ligand-to-Metal Charge Transfer (LMCT) to enable the generation of a chlorine radical which acts as a powerful hydrogen atom transfer reagent capable of abstracting strong electron-rich C­(sp3)–H bonds. Of note is that the chlorocuprate catalyst is an exceedingly mild oxidant (0.5 V vs SCE) and that a proposed protodemetalation mechanism offers a broad scope of electron-deficient olefins, offering high diastereoselectivity in the case of endocyclic alkenes. The coupling of chlorine radical generation with Cu reduction through LMCT enables the generation of a highly active HAT reagent in an operationally simple and atom economical protocol.