Visible-Light-Induced Alkoxyl Radicals Enable α-C(sp3)-H Bond Allylation
Jing Zhang,
Dan Liu,
Song Liu,
Yuanyuan Ge,
Yu Lan,
Yiyun Chen
Affiliations
Jing Zhang
State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
Dan Liu
State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
Song Liu
School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400030, China
Yuanyuan Ge
State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
Yu Lan
School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400030, China; Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, China; Corresponding author
Yiyun Chen
State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China; Corresponding author
Summary: The alkoxyl radical is an essential reactive intermediate in mechanistic studies and organic synthesis with hydrogen atom transfer (HAT) reactivity. However, compared with intramolecular 1,5-HAT or intermolecular HAT of alkoxyl radicals, the intramolecular 1,2-HAT reactivity has been limited to theoretical studies and rarely synthetically utilized. Here we report the first selective 1,2-HAT of alkoxyl radicals for α-C(sp3)-H bond allylation of α-carbonyl, α-cyano, α-trifluoromethyl, and benzylic N-alkoxylphthalimides. The mechanistic probing experiments, electron paramagnetic resonance (EPR) studies, and density functional theory (DFT) calculations confirmed the 1,2-HAT reactivity of alkoxyl radicals, and the use of protic solvents lowered the activation energy by up to 10.4 kcal/mol to facilitate the α-C(sp3)-H allylation reaction. : Organic Chemistry; Organic Reaction; Physical Organic Chemistry Subject Areas: Organic Chemistry, Organic Reaction, Physical Organic Chemistry
