- Electrochemical Trifluoromethoxylation of (Hetero)aromatics with a Trifluoromethyl Source and Oxygen
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Trifluoromethoxylated aromatics (ArOCF3) are valuable structural motifs in the area of drug discovery due to the enhancement of their desired physicochemical properties upon the introduction of the trifluoromethoxy group (CF3O). Although significant progress has been made recently in the introduction of CF3O group into aromatics, current methods either require the use of expensive trifluoromethoxylation reagents or require harsh reaction conditions. We present a conceptually new and operationally simple protocol for the direct C?H trifluoromethoxylation of (hetero)aromatics by the combination of the readily available trifluoromethylating reagent and oxygen under electrochemical reaction conditions. This reaction proceeds through the initial generation of CF3 radical followed by conversion to CF3O radical, addition to (hetero)aromatics and rearomatization. The utility of this electrochemical trifluoromethoxylation is illustrated by the direct incorporation of CF3O group into a variety of (hetero)aromatics as well as bio-relevant molecules.
- Ouyang, Yao,Qing, Feng-Ling,Xu, Xiu-Hua
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supporting information
(2021/12/06)
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- Radical C?H Trifluoromethoxylation of (Hetero)arenes with Bis(trifluoromethyl)peroxide
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Trifluoromethoxylated (hetero)arenes are of great interest for several disciplines, especially in agro- and medicinal chemistry. Radical C?H trifluoromethoxylation of (hetero)arenes represents an attractive approach to prepare such compounds, but the high cost and low atom economy of existing .OCF3 radical sources make them unsuitable for the large-scale synthesis of trifluoromethoxylated building blocks. Herein, we introduce bis(trifluoromethyl)peroxide (BTMP, CF3OOCF3) as a practical and efficient trifluoromethoxylating reagent that is easily accessible from inexpensive bulk chemicals. Using either visible light photoredox or TEMPO catalysis, trifluoromethoxylated arenes could be prepared in good yields under mild conditions directly from unactivated aromatics. Moreover, TEMPO catalysis allowed for the one-step synthesis of valuable pyridine derivatives, which have been previously prepared via multi-step approaches.
- Dix, Stefan,Golz, Paul,Schmid, Jonas R.,Riedel, Sebastian,Hopkinson, Matthew N.
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supporting information
p. 11554 - 11558
(2021/07/09)
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- Photocatalytic trifluoromethoxylation of arenes and heteroarenes in continuous-flow
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The first example of photocatalytic trifluoromethoxylation of arenes and heteroarenes under continuous-flow conditions is described. Application of continuous-flow microreactor technology allowed to reduce the residence time up to 16 times in comparison t
- Cendón, Borja,Gulías, Moisés,Ho, Michelle,No?l, Timothy,Nyuchev, Alexander V.,Sambiagio, Carlo,Struijs, Job J. C.,Wan, Ting,Wang, Ying
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supporting information
p. 1305 - 1312
(2020/07/10)
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- Radical Trifluoromethoxylation of Arenes Triggered by a Visible-Light-Mediated N?O Bond Redox Fragmentation
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A simple trifluoromethoxylation method enables non-directed functionalization of C?H bonds on a range of substrates, providing access to aryl trifluoromethyl ethers. This light-driven process is distinctly different from conventional procedures and occurs through an OCF3 radical mechanism mediated by a photoredox catalyst, which triggers an N?O bond fragmentation. The pyridinium-based trifluoromethoxylation reagent is bench-stable and provides access to synthetic diversity in lead compounds in an operationally simple manner.
- Jelier, Benson J.,Tripet, Pascal F.,Pietrasiak, Ewa,Franzoni, Ivan,Jeschke, Gunnar,Togni, Antonio
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supporting information
p. 13784 - 13789
(2018/09/14)
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- Design, synthesis and biological evaluation of novel 4-(2-fluorophenoxy)quinoline derivatives as selective c-Met inhibitors
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Two novel series of 6,7-disubstituted-4-(2-fluorophenoxy)quinoline derivatives bearing 1H-imidazole-4-carboxamido or (E)-3-hydrosulfonylacrylamido motifs (16–31 and 32–42) were designed, synthesized and evaluated for their in vitro cytotoxic activity. Most of the compounds exhibited moderate to excellent potency against tested three cell lines, and fifteen compounds were further examined for their inhibitory activity against c-Met kinase. The most promising compound 16 (c-Met kinase [IC50]?=?1.1?nM) demonstrated high selectivity and remarkable cytotoxicity against HT-29, MKN-45 and A549 cells with IC50values of 0.08, 0.22 and 0.07?μM, which were 3.1-, 1.4- and 2.1-fold more active than Foretinib. The preliminary structure-activity relationships as well as molecular docking disclosed that 1H-imidazole-4-carboxamido as a linker was of great importance for the antitumor activity.
- Wang, Xiaoqiang,Jiang, Nan,Zhao, Sijia,Xi, Shuancheng,Wang, Jiao,Jing, Tongfei,Zhang, Wenyu,Guo, Ming,Gong, Ping,Zhai, Xin
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p. 886 - 896
(2017/02/05)
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- Metal-Free Oxidation of Primary Amines to Nitriles through Coupled Catalytic Cycles
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Synergism among several intertwined catalytic cycles allows for selective, room temperature oxidation of primary amines to the corresponding nitriles in 85-98 % isolated yield. This metal-free, scalable, operationally simple method employs a catalytic quantity of 4-acetamido-TEMPO (ACT; TEMPO=2,2,6,6-tetramethylpiperidine N-oxide) radical and the inexpensive, environmentally benign triple salt oxone as the terminal oxidant under mild conditions. Simple filtration of the reaction mixture through silica gel affords pure nitrile products.
- Lambert, Kyle M.,Bobbitt, James M.,Eldirany, Sherif A.,Kissane, Liam E.,Sheridan, Rose K.,Stempel, Zachary D.,Sternberg, Francis H.,Bailey, William F.
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supporting information
p. 5156 - 5159
(2016/04/09)
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- 2-, 3-, and 4-(Trifluoromethoxy)phenyllithiums: Versatile intermediates offering access to a variety of new organofluorine compounds
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Consecutive treatment of (trifluoromethoxy)benzene with sec-butyllithium and electrophilic reagents affords previously inaccessible ortho-substituted derivatives in generally excellent yields. 2-(Trifluoromethoxy)phenyllithium acts as the key intermediate. The 3- and 4-isomers can readily be generated from the corresponding 3- and 4-bromo precursors by halogen-metal interconversion with butyllithium or tertbutyllithium. Upon trapping of the 2-, 3- and 4-(trifluoromethoxy)phenyllithiums with 11 different electrophiles the expected products were formed in generally high yields. Only the attempted nucleophilic addition of 2-(trifluoromethoxy)phenyllithium to oxirane did not succeed. This failure is tentatively attributed to a lowering of the nucleophilicity by fluorine-lithium interactions. Conformationally restricted analogs - i.e., 2,2-difluoro-1,3-benzodioxol-4-phenyllithium and its 5-fluoro- and 5-bromo-substituted congeners - did indeed react smoothly with oxirane, affording the adducts in ordinary yields.
- Castagnetti, Eva,Schlosser, Manfred
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p. 691 - 695
(2007/10/03)
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- Method for producing aromatic nitriles
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PCT No. PCT/EP98/00696 Sec. 371 Date Aug. 17, 1999 Sec. 102(e) Date Aug. 17, 1999 PCT Filed Feb. 9, 1998 PCT Pub. No. WO98/37058 PCT Pub. Date Aug. 27, 1998A process for preparing aromatic nitriles from corresponding chloroaromatics by reaction with cyanides.
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