Hydrogen Atom Transfers in B12 Enzymes

2007 ◽  
pp. 1473-1495
Author(s):  
Ruma Banerjee ◽  
Donald G. Truhlar ◽  
Agnieszka Dybala-Defratyka ◽  
Piotr Paneth
Keyword(s):  
Hydrogen Atom ◽  
Hydrogen Atom Transfers

scholarly journals Site-selective remote C(sp3)–H heteroarylation of amides via organic photoredox catalysis

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Hui Chen ◽  
Wenjing Fan ◽  
Xiang-Ai Yuan ◽  
Shouyun Yu
Keyword(s):  
Hydrogen Atom ◽  
Room Temperature ◽  
Ph Value ◽  
Metal Free ◽  
Selective Functionalization ◽  
Site Selectivity ◽  
Hydrogen Atom Transfers ◽  
Site Selective ◽  
Neutral Conditions ◽  
Potential Complement

Abstract Radical translocation processes triggered by nitrogen-centered radicals (NCRs), such as 1,5-hydrogen atom transfers (1,5-HAT), demonstrated by the well-established Hofmann-Löffler-Freytag (HLF) reaction, provide an attractive approach for the controllable and selective functionalization of remote inert C(sp3)–H bonds. Here we report an amidyl radical-triggered site-selective remote C(sp3)–H heteroarylation of amides under organic photoredox conditions. This approach provides a mild and highly regioselective reaction affording remote C(sp3)–H heteroarylated amides at room temperature under transition-metal free, weakly basic, and redox-neutral conditions. Non-prefunctionalized heteroarenes, such as purines, thiazolopyridines, benzoxazole, benzothiazoles, benzothiophene, benzofuran, thiazoles and quinoxalines, can be alkylated directly. Sequential and orthogonal C–H functionalization of different heteroarenes by taking advantage pH value or polarity of radicals has also been achieved. DFT calculations explain and can predict the site-selectivity and reactivity of this reaction. This strategy expands the scope of the Minisci reaction and serves as its alternative and potential complement.

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