159298-87-0Relevant articles and documents
Insertion of Diazo Esters into C-F Bonds toward Diastereoselective One-Carbon Elongation of Benzylic Fluorides: Unprecedented BF3Catalysis with C-F Bond Cleavage and Re-formation
Wang, Fei,Nishimoto, Yoshihiro,Yasuda, Makoto
, p. 20616 - 20621 (2021/11/23)
Selective transformation of C-F bonds remains a significant goal in organic chemistry, but C-F insertion of a one-carbon-atom unit has never been established. Herein we report the BF3-catalyzed formal insertion of diazo esters as one-carbon-atom sources into C-F bonds to accomplish one-carbon elongation of benzylic fluorides. A DFT calculation study revealed that the BF3 catalyst could contribute to both C-F bond cleavage and re-formation. This elongation provided α-fluoro-α,β-diaryl esters with a high level of diastereoselectivity. Various benzylic fluorides and diazo esters were applicable. The synthetic utility of this method was demonstrated by the synthesis of a fluoro analogue of a compound that is used as a transient receptor and potential canonical channel inhibitor.
Copper-Catalyzed Functionalization of Benzylic C-H Bonds with N-Fluorobenzenesulfonimide: Switch from C-N to C-F Bond Formation Promoted by a Redox Buffer and Br?nsted Base
Buss, Joshua A.,Golden, Dung L.,Stahl, Shannon S.,Vasilopoulos, Aristidis
supporting information, p. 5749 - 5752 (2020/10/02)
A copper catalyst in combination with N-fluorobenzenesulfonimide (NFSI) has been reported to functionalize benzylic C-H bonds to the corresponding benzylic sulfonimides via C-N coupling. Here, we reported a closely related Cu-catalyzed method with NFSI that instead leads to C-F coupling. This switch in selectivity arises from changes to the reaction conditions (Cu/ligand ratio, temperature, addition of base) and further benefits from inclusion of MeB(OH)2 in the reaction. MeB(OH)2 is shown to serve as a "redox buffer"in the reaction, responsible for rescuing inactive Cu(II) for continued promotion of fluorination reactivity.
METHODS AND COMPOSITIONS FOR DIRECT RADIOACTIVE LABELING OF BIO-ACTIVE MOLECULES AND BUILDING BLOCKS
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Paragraph 00119; 00120; 00121, (2015/11/02)
Methods of direct radioactive labeling a carbon containing compound having an sp3 C-H bond are provided. Methods of carrier-free 18F fluorination of a carbon containing compound mediated by manganese salen complexes or manganese porphyrin complexes comprising weakly coordinated anions as axial ligands are provided. Methods of "dry-down" free radioactive labeling of a carbon containing compound having an sp3 C-H bond are provided. The radioactively labeled products of the methods are provided.