Site-Selective Pyridylic C-H Functionalization by Photocatalytic Radical Cascades

被引:25
作者
Kim, Myojeong [1 ,2 ]
You, Euna [1 ,2 ]
Kim, Jieun [1 ,2 ]
Hong, Sungwoo [1 ,2 ]
机构
[1] Korea Adv Inst Sci & Technol KAIST, Dept Chem, Daejeon 34141, South Korea
[2] Inst Basic Sci IBS, Ctr Catalyt Hydrocarbon Functionalizat, Daejeon 34141, South Korea
关键词
C-H Functionalization; Heterocycles; Photocatalysis; Radicals; Reaction Mechanisms; VISIBLE-LIGHT PHOTOREDOX; ALKYLATION; ARYL; TRIFLUOROMETHYLTHIOLATION; PHARMACEUTICALS; HETEROARENES; HETEROCYCLES; FLUORINATION; PRECURSORS; OXIDATION;
D O I
10.1002/anie.202204217
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
An efficient pyridylic C(sp(3))-H functionalization has been developed through photocatalytic radical-mediated fluoroalkylation or cascade reactions. This method is enabled by the reversible formation of alkylidene dihydropyridine intermediates via the facile enolate formation of C4-alkyl N-amidopyridinium salts in the absence of an external base, thereby establishing the conditions necessary for subsequent intermolecular radical trapping. Rapid structural diversification of the pyridylic site can be achieved through photocatalytic multicomponent cascade reactions involving alkene trifluoromethylation, SO2-reincorporation, and sulfonyl radical addition. This operationally simple method features a broad substrate scope and high chemoselectivity and offers a unique approach for the rational modification of the heterobenzylic C-H bonds of pyridines and quinolines with uniform site-selective control. Furthermore, experimental and theoretical studies were performed to elucidate the reaction mechanism.
引用
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页数:9
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