- Stereoselective formation of Z-monofluoroalkenes by nickel-catalyzed defluorinative coupling of gem?difluoroalkenes with lithium organoborates
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A method for stereoselective construction of Z-monofluoroalkenes by nickel-catalyzed defluorinative coupling of gem?difluoroalkenes in mild conditions was described. The combination of lithium organoborate and ZnBr2 generated in situ lithium ar
- Huang, Weichen,Shen, Qilong,Xiao, Yisa
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supporting information
(2022/02/02)
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- Fluoride-Triggered Synthesis of 1-Aryl-2,2-difluoroalkenes via Desilylative Defluorination of (1-Aryl)-2,2,2-trifluoroethyl-silanes
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An efficient route for the synthesis of 1-aryl-2,2-difluoroalkenes via 1,2-desilylative defluorination is disclosed. Only a catalytic amount of fluoride source is required to initiate the desilylation and afford gem-difluoroalkenes in very good to quantitative yields, using mild reaction conditions in dimethyl carbonate as a green solvent. This reaction uses (1-aryl)-2,2,2-trifluoroethyl-silanes, which are easily prepared via the insertion reaction of trifluoroethyl diazo alkanes into the Si-H bond of tertiary organosilanes. (1-Aryl)-perfluoroalkyl-silanes cleanly afford the corresponding (Z)-1-benzylideneperfluoroalkanes, which upon hydrodefluorination furnish the (E)-β(perfluoroalkyl)styrene derivatives with excellent yield and complete stereoselectivity. A one-pot system involving sequential insertion and desilylative-defluorination is also suitable for this transformation. This method demonstrates the usefulness of organosilanes toward the preparation of fluorinated alkenes as synthetically useful targets.
- Carreras, Virginie,Ollevier, Thierry
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p. 13160 - 13168
(2021/09/18)
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- Acid-Catalyzed Hydrothiolation of gem-Difluorostyrenes to Access α,α-Difluoroalkylthioethers
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The substitution of hydrogen atoms with fluorine in bioactive molecules can greatly impact physicochemical, pharmacokinetic, and pharmacodynamic properties. However, current synthetic methods cannot readily access many fluorinated motifs, which impedes utilization of these groups. Thus, the development of new methods to introduce fluorinated functional groups is critical for developing the next generation of biological probes and therapeutic agents. The synthesis of one such substructure, the α,α-difluoroalkylthioether, typically requires specialized conditions that necessitate early-stage installation. A late-stage and convergent approach to access α,α-difluoroalkylthioethers could involve nucleophilic addition of thiols across gem-difluorostyrenes. Unfortunately, under basic conditions, nucleophilic addition to gem-difluorostyrenes generates an anionic intermediate that can undergo facile elimination of fluoride to generate α-fluorovinylthioethers. To overcome this decomposition, we herein exploit an acid-based catalyst system to facilitate simultaneous nucleophilic addition and protonation of the unstable intermediate. Ultimately, the optimized mild conditions afford the desired α,α-difluoroalkylthioethers in high selectivity and moderate to excellent yields. These α,α-difluoroalkylthioethers are less nucleophilic and more oxidatively stable relative to nonfluorinated thioethers, suggesting the potential application of this unexplored functional group in biological probes and therapeutic agents.
- Sorrentino, Jacob P.,Orsi, Douglas L.,Altman, Ryan A.
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p. 2297 - 2311
(2021/02/06)
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- Visible-light-promotedE-selective synthesis of α-fluoro-β-arylalkenyl sulfidesviathe deoxygenation/isomerization process
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Regioselective synthesis of α-fluoro-β-arylalkenyl sulfides has been established withgem-difluoroalkenes and sodium sulfinates in a transition-metal-free manner. A series of control experiments were executed to demonstrate thiol radicals and anions as the proposed intermediates. Notably, regioselectiveZ→Eisomerization was achieved under green light irradiation in the absence of a photoinitiator.
- Li, Yuxiu,Li, Xiangqian,Li, Xiaowei,Shi, Dayong
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supporting information
p. 2152 - 2155
(2021/03/06)
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- -Annulation of gem-Difluoroalkenes and Pyridinium Ylides: Access to Functionalized 2-Fluoroindolizines
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A [3 + 2]-annulation of gem-difluoroalkenes and pyridinium ylides was developed employing ambient air as the sole oxidant in an open-vessel manner, affording a series of multifunctionalized 2-fluoroindolizines in moderate to good yields. In this reaction, gem-difluoroalkene acts as a C2 synthon and entirely avoids the competitive addition-elimination process, which provides facile access to 2-fluoroindolizines.
- Zhang, Jun-Qi,Hu, Dandan,Song, Jinyu,Ren, Hongjun
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p. 4646 - 4660
(2021/04/06)
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- A one-step synthesis of gem-difluoroolefins from alcohols
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The development of efficient protocols for the synthesis of gem-difluoroolefins has received increasing attention. Given the ubiquity of hydroxyl group in biologically active molecules and synthetic intermediates, we developed a one-step protocol for the conversions of alcohols into gem-difluoroolefins. The reactions of alcohols with Ph3P+CF2CO2?/Burgess reagent in DMSO occurred smoothly to afford the final products in moderate to high yields. DMSO is not only necessary for the oxidation process, but also important for the stabilization of phosphonium ylide by trapping difluorocarbene.
- Gu, Jinying,Lin, Jin-Hong,Tang, Ting,Xiao, Can,Xiao, Ji-Chang,Xiao, Xuan,Yao, Xu,Yu, Jiao,Zheng, Xing
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- Autocatalytic Synthesis of Thioesters via Thiocarbonylation of gem-Difluoroalkenes
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Herein, we report a new method for the synthesis of acyethanethioates via thiocarbonylation of gem-difluoroalkenes with thiols. This reaction provides a new pathway to prepare thioesters under mild conditions without the use of any additives. Mechanistic
- Jiang, Xinpeng,Wang, Guan,Zheng, Zicong,Yu, Xiaohui,Hong, Ye,Xia, Haoqi,Yu, Chuanming
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supporting information
p. 9762 - 9766
(2020/12/21)
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- Organocatalytic strategy for hydrophenolation of gem-difluoroalkenes
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Gem-difluoroalkenes are an easily accessed fluorinated functional group, and a useful intermediate for elaborating into more complex fluorinated compounds. Currently, most functionalization reactions of gem-difluoroalkenes, with or without a transition metal-based catalyst system, involve the addition or removal of a fluorine atom to generate trifluorinated or monofluorinated products, respectively. In contrast, we present a complementary “fluorine-retentive” reaction that exploits an organocatalytic strategy to add phenols across gem-difluoroalkenes to deliver β,β-difluorophenethyl arylethers. The products are produced in good to moderate yields and selectivities, thus providing a range of compounds that are underrepresented in the synthetic and medicinal chemistry literature.
- Orsi, Douglas L.,Yadav, M. Ramu,Altman, Ryan A.
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p. 4325 - 4336
(2019/04/25)
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- Pd-Catalyzed Selective Carbonylation of gem-Difluoroalkenes: A Practical Synthesis of Difluoromethylated Esters
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The first catalyst for the alkoxycarbonylation of gem-difluoroalkenes is described. This novel catalytic transformation proceeds in the presence of Pd(acac)2/1,2-bis((di-tert-butylphosphan-yl)methyl)benzene (btbpx) (L4) and allows for an efficient and straightforward access to a range of difluoromethylated esters in high yields and regioselectivities. The synthetic utility of the protocol is showcased in the practical synthesis of a Cyclandelate analogue using this methodology as the key step.
- Liu, Jiawang,Yang, Ji,Ferretti, Francesco,Jackstell, Ralf,Beller, Matthias
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supporting information
p. 4690 - 4694
(2019/03/13)
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- Direct α-Monofluoroalkenylation of Heteroatomic Alkanes via a Combination of Photoredox Catalysis and Hydrogen-Atom-Transfer Catalysis
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In this study, a new C(sp3)-H monofluoroalkenylation reaction involving cooperative visible-light photoredox catalysis and hydrogen-atom-transfer catalysis to afford products generated by selective hydrogen abstraction and radical-radical cross-coupling was described. This mild, efficient reaction shows high regioselectivity for the α-carbon atoms of amines, ethers, and thioethers and thus allows the preparation of monofluoroalkenes bearing various substituents. The reaction was applied to two bioactive molecules, indicating its utility for late-stage monofluoroalkenylation of compounds with inert C(sp3)-H bonds.
- Tian, Hao,Xia, Qing,Wang, Qiang,Dong, Jianyang,Liu, Yuxiu,Wang, Qingmin
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supporting information
p. 4585 - 4589
(2019/06/17)
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- Photoredox-Coupled F-Nucleophilic Addition: Allylation of gem-Difluoroalkenes
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A novel strategy for the expedient construction of CF3-embeded tertiary/quarternary carbon centers was developed by taking advantage of photoredox catalysis. Thanks to a key step of single-electron oxidation, electron-rich gem-difluoroalkenes, which otherwise are essentially reluctant towards F-nucleoplilic addition, now readily participate in this fluoroallylation reaction. Furthermore, this strategy provides an elegant example for the generation, as well as functionalization, of α-CF3-substituted benzylic radical intermediates using cheap and readily available starting materials.
- Liu, Haidong,Ge, Liang,Wang, Ding-Xing,Chen, Nan,Feng, Chao
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supporting information
p. 3918 - 3922
(2019/02/19)
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- Organocatalytic Nucleophilic Substitution Reaction of gem-Difluoroalkenes with Ketene Silyl Acetals
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An organocatalytic nucleophilic substitution reaction of gem-difluoroalkenes with ketene silyl acetals was developed. Phosphazene P4-tBu effectively catalyzed the reaction under mild conditions to provide monofluoroalkenes possessing an alkoxycarbonylmethyl group in high yields with high Z selectivities.
- Kondoh, Azusa,Koda, Kazumi,Terada, Masahiro
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supporting information
p. 2277 - 2280
(2019/03/26)
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- Regio- and Stereoselective Alkenylation of Allenoates with gem-Difluoroalkenes: Facile Access to Fluorinated 1,4-Enynes Bearing an All-Carbon Quaternary Center
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A regio- and stereoselective synthesis of fluorinated 1,4-enynes bearing an all-carbon quaternary center at the propargylic position is developed. The synthesis starts from readily available allenoates and gem-difluoroalkenes and proceeds via a key alkyny
- Zhang, Qi-Qi,Chen, Shi-Yong,Lin,Wang, Honggen,Li, Qingjiang
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supporting information
p. 3123 - 3126
(2019/05/02)
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- Trifluoromethylation and Monofluoroalkenylation of Alkenes through Radical–Radical Cross-Coupling
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The first visible-light-induced trifluoromethylation and monofluoroalkenylation of simple alkenes via a challenging radical–radical cross-coupling step was achieved. This method provided a mild, step-economical and redox-neutral route to privileged two different fluorinated difunctionalized allyl compounds. The utility of this method is illustrated by late-stage modification of medically important molecules.
- Wang, Qiang,Qu, Yi,Tian, Hao,Liu, Yuxiu,Song, Hongjian,Wang, Qingmin
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supporting information
p. 8686 - 8690
(2019/06/17)
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- Rhodium-Catalyzed Defluorinative Vinylation of gem-Difluoroalkenes for the Synthesis of 2-Fluoro-1,3-dienes
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Herein, we present a strategy for the formation of 2-fluoro-1,3-diene derivatives via rhodium-catalyzed direct C(sp2)—C(sp2) cross-coupling of gem-difluoroalkenes and acrylamides. By merging Rh(III)-catalyzed C(sp2)–H bond activation and nucleophilic addition/F-elimination of gem-difluoroalkene, an efficient defluorinative vinylation reaction is uncovered, which leads to the generation of 2-fluoro-1,3-dienes in moderate to good yields with excellent stereoselectivity under mild conditions. Preliminary mechanistic study suggests unique effects of fluorine substituents which allow the reactivity profile not observed with the congeners bearing heavier halides.
- Song, Shengjin,Liu, Huan,Wang, Lu,Zhu, Chuan,Loh, Teck-Peng,Feng, Chao
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supporting information
p. 1036 - 1040
(2019/09/16)
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- Model II fluorine asia [...] inner salt synthesis and its application
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The present invention provides synthesis and application of difluoro methylene phosphorus inner salt, wherein the compound has a structure shown in Formula A: (R1R2R3)P+CF2CO2 -. The definitions of substituent groups are described in the specification. Th
- -
-
Paragraph 0274-0276
(2018/01/11)
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- Copper-Catalyzed Regioselective Monodefluoroborylation of Polyfluoroalkenes en Route to Diverse Fluoroalkenes
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Monodefluoroborylation of polyfluoroalkenes has been achieved in a regioselective manner under mild conditions via copper catalysis. The method has shown an extremely broad scope of substrates, including (difluorovinyl)arenes, tetrafluoroethylene (TFE), (
- Sakaguchi, Hironobu,Uetake, Yuta,Ohashi, Masato,Niwa, Takashi,Ogoshi, Sensuke,Hosoya, Takamitsu
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supporting information
p. 12855 - 12862
(2017/09/25)
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- Synthesis of tetrazines from: Gem -difluoroalkenes under aerobic conditions at room temperature
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An efficient and green procedure for the synthesis of tetrazines has been developed based on an old chemistry reported by Carboni in 1958. Both symmetric and asymmetric 3,6-disubstituted 1,2,4,5-tetrazines can be obtained in moderate to high yields from t
- Fang, Zheng,Hu, Wen-Li,Liu, De-Yong,Yu, Chu-Yi,Hu, Xiang-Guo
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supporting information
p. 1299 - 1302
(2017/08/15)
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- Manganese-catalyzed synthesis of monofluoroalkenes: Via C-H activation and C-F cleavage
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The manganese-catalyzed α-fluoroalkenylation of arenes via C-H activation and C-F cleavage has been described. This protocol provides a very useful method for the synthesis of monofluoroalkenes with predominant unconventional E-isomer selectivity which complements the existing strategies for the access to these molecular architectures. In addition, the selectivity of β-defluorination in the catalytic cycle not only determines the configurations of the products but also obviates the use of external oxidants, providing a good example in the exploitation of manganese-catalyzed redox-neutral C-H transformations.
- Cai, Sai-Hu,Ye, Lu,Wang, Ding-Xing,Wang, Yi-Qiu,Lai, Lin-Jie,Zhu, Chuan,Feng, Chao,Loh, Teck-Peng
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supporting information
p. 8731 - 8734
(2017/08/09)
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- Reaction of Diazo Compounds with Difluorocarbene: An Efficient Approach towards 1,1-Difluoroolefins
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A transition-metal-free difluoromethylenation of diazo compounds that proceeds under mild conditions has been developed and is based on the use of TMSCF2Br as the difluoromethylene source and tetrabutylammonium bromide (TBAB) as the promoter. T
- Zhang, Zhikun,Yu, Weizhi,Wu, Chenggui,Wang, Chengpeng,Zhang, Yan,Wang, Jianbo
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p. 273 - 277
(2016/01/25)
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- Direct Difluoromethylenation of Carbonyl Compounds by Using TMSCF3: The Right Conditions
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A deoxygenative difluoromethylenation of carbonyl compounds has been developed by using readily available, inexpensive trifluoromethyltrimethylsilane, LiI, and PPh3. The presence of the Li+ion prevents the unproductive exhaustion of trifluoromethyltrimethylsilane (TMSCF3) by keeping the soluble free fluoride concentration in the reaction medium under control. The strategy of combining solvents to increase the reactivity and thereby reduce the reaction temperature and time is disclosed.
- Krishnamoorthy, Sankarganesh,Kothandaraman, Jotheeswari,Saldana, Jacqueline,Prakash, G. K. Surya
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supporting information
p. 4965 - 4969
(2016/10/26)
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- One-pot synthesis of gem-difluorostyrenes from benzyl bromide via olefination of phosphonium ylide with difluorocarbene
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A new approach for the synthesis of gem-difluorostyrenes from benzyl bromide is described. Quaternization of triphenylphosphine with benzyl bromide to give phosphonium salts, deprotonation of the corresponding phosphonium salts to produce phosphonium ylide, and the subsequent olefination of phosphonium ylide with difluorocarbene generated from difluoromethylene phosphobetaine (Ph3P+CF2CO2-) by decarboxylation can occur smoothly in one-pot, furnishing the final gem-difluorostyrenes in good yields.
- Deng, Xiao-Yun,Lin, Jin-Hong,Xiao, Ji-Chang
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p. 116 - 120
(2015/11/10)
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- Wittig gem-difluoroolefination of aldehydes with difluoromethyltriphenylphosphonium bromide
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Wittig reaction of aldehydes with difluoromethyltriphenylphosphonium bromide leading to gem-difluoroolefins in moderate yields is described. The reaction displays a good substrate scope including aryl, heteroaryl and α,β-unsaturated aldehydes. Difluoromethyltriphenylphosphonium bromide could be easily prepared and stored for a long time under air atmosphere. The salt exhibits high thermal stability demonstrated by thermogravimetric analysis. Its structure was confirmed by NMR spectroscopy and single crystal X-ray analysis.
- Li, Qiang,Lin, Jin-Hong,Deng, Zu-Yong,Zheng, Jian,Cai, Ji,Xiao, Ji-Chang
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- Switchable 2,2,2-trifluoroethylation and gem-difluorovinylation of organoboronic acids with 2,2,2-trifluorodiazoethane
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The transition-metal-free 2,2,2-trifluoroethylation and gem-difluorovinylation of arylboronic acids were developed. By employing different reaction conditions, these transformations provide both (2,2,2-trifluoroethyl)arenes and gem-difluorovinylarenes fro
- Wu, Guojiao,Deng, Yifan,Wu, Chaoqiang,Wang, Xi,Zhang, Yan,Wang, Jianbo
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supporting information
p. 4477 - 4481
(2014/08/05)
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- Deoxygenative gem-difluoroolefination of carbonyl compounds with (chlorodifluoromethyl)trimethylsilane and triphenylphosphine
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Background: 1,1-Difluoroalkenes cannot only be used as valuable precursors for organic synthesis, but also act as bioisosteres for enzyme inhibitors. Among various methods for their preparation, the carbonyl olefination with difluoromethylene phosphonium ylide represents one of the most straightforward methods. Results: The combination of (chlorodifluoromethyl)trimethylsilane (TMSCF2Cl) and triphenylphosphine (PPh3) can be used for the synthesis of gem-difluoroolefins from carbonyl compounds. Comparative experiments demonstrate that TMSCF2Cl is superior to (bromodifluoromethyl)trimethylsilane (TMSCF2Br) and (trifluoromethyl)trimethylsilane (TMSCF3) in this reaction. Conclusion: Similar to many other Wittig-type gem-difluoroolefination reactions in the presence of PPh3, the reaction of TMSCF2Cl with aldehydes and activated ketones is effective.
- Wang, Fei,Li, Lingchun,Ni, Chuanfa,Hu, Jinbo
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supporting information
p. 344 - 351
(2014/03/21)
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- Decarboxylative julia-kocienski gem-difluoro-olefination of 2-pyridinyl sulfonyldifluoroacetate
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The decarboxylation of potassium 2-pyridinyl sulfonyldifluoroacetate and its subsequent reaction with aldehydes was found to be an efficient approach for the Julia-Kocienski reaction under mild conditions to give gem-difluoro olefins in moderate to excell
- Wang, Xiao-Ping,Lin, Jin-Hong,Xiao, Ji-Chang,Zheng, Xing
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p. 928 - 932
(2014/03/21)
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- Decarboxylative Julia-Kocienski gem-Difluoro-Olefination of 2-Pyridinyl Sulfonyldifluoroacetate
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The decarboxylation of potassium 2-pyridinyl sulfonyldifluoroacetate and its subsequent reaction with aldehydes was found to be an efficient approach for the Julia-Kocienski reaction under mild conditions to give gem-difluoro olefins in moderate to excellent yields. Owing to its high stability in the pure state and its easy decarboxylation in polar solvents, potassium 2-pyridinyl sulfonyldifluoroacetate is expected to be an efficient gem-difluoro-olefination reagent. The decarboxylation of potassium 2-pyridinyl sulfonyldifluoroacetate and its subsequent reaction with aldehydes is an efficient approach for the Julia-Kocienski reaction under mild conditions to give gem-difluoro olefins in moderate to excellent yields.
- Wang, Xiao-Ping,Lin, Jin-Hong,Xiao, Ji-Chang,Zheng, Xing
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p. 928 - 932
(2015/10/05)
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- Synthesis of alkyl aryl(heteroaryl)acetates from N-oxides, 1,1-difluorostyrenes, and alcohols
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Derivatives of aryl(heteroaryl)acetic acids or aryl(heteroaryl)methanes are formed from imidazole or thiazole N-oxide, 1,1-difluorostyrene, and an alcohol, amine, or water in a three-component reaction, which probably occurs via 1,3-dipolar cycloaddition.
- Loska, Rafal,Szachowicz, Katarzyna,Szydlik, Dorota
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supporting information
p. 5706 - 5709
(2013/12/04)
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- Conversion between difluorocarbene and difluoromethylene ylide
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The interconversion between difluoromethylene ylide and difluorocarbene is described. The difluoromethylene ylide precursor, Ph3P +CF2CO2-, could be turned into an efficient difluorocarbene reagent, w
- Zheng, Jian,Lin, Jin-Hong,Cai, Ji,Xiao, Ji-Chang
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supporting information
p. 15261 - 15266
(2013/11/06)
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- Synthesis and decarboxylative Wittig reaction of difluoromethylene phosphobetaine
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A key intermediate, difluoromethylene phosphobetaine, in the Wittig reaction of ClCF2CO2Na-Ph3P with aldehydes was synthesized and characterized, which confirmed the reaction mechanism. The decarboxylation of this stable intermediate was a convenient approach for Wittig difluroolefination. Its reactivity could be adjusted by the modification of the substituent on the phosphorus.
- Zheng, Jian,Cai, Ji,Lin, Jin-Hong,Guo, Yong,Xiao, Ji-Chang
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supporting information
p. 7513 - 7515
(2013/08/23)
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- The use of methyl 2,2-difluoro-2-(fluorosulfonyl)acetate as the difluorocarbene source to generate an in situ source of difluoromethylene triphenylphosphonium ylide
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Under moderate conditions in the presence of a demethylating reagent, such as iodide, methyl 2,2,-difluoro-2-(fluorosulfonyl)acetate (MDFA) releases difluorocarbene, which in the presence of triphenylphosphine forms difluoromethylene triphenylphosphonium ylide. When the process is carried out also in the presence of aldehydes or activated ketones, the ensuing in situ Wittig-type reaction of the ylide with the carbonyl reactants produces 1,1-difluoroalkenes in good yield. Density Functional Theory calculations were used to provide new estimates of the energies and structures of singlet and triplet states of CH2:, CHF:, and CF2: carbenes, as well as those of their respective triphenylphosphonium ylides.
- Thomoson, Charles S.,Martinez, Henry,Dolbier Jr., William R.
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- Nucleophilic (phenylsulfonyl)difluoromethylation of alkyl halides using PhSO2CF2SiMe3: Preparation of gem-difluoroalkenes and trifluoromethyl compounds
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Nucleophilic (phenylsulfonyl)difluoromethylation of both alkyl iodides and bromides was successfully accomplished by using CsF/15-crown-5 as an initiating system in DME, and the amount of 15-crown-5 was found to be critical to the yield of the product. The prepared (phenylsulfonyl)difluoromethylated alkanes were converted into gem-difluoroalkenes by a base-mediated 1,2-elimination reaction, and the latter species could be further transformed into trifluoromethyl compounds in the presence of KF/18-crown-6 or TBAF.
- Zhu, Lingui,Li, Ya,Zhao, Yanchuan,Hu, Jinbo
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supporting information; experimental part
p. 6150 - 6152
(2010/12/24)
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- Difluoromethyl 2-pyridyl sulfone: A new gem-difluoroolefination reagent for aldehydes and ketones
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Chemical equation presented Difluoromethyl 2-pyridyl sulfone, a previously unknown compound, was found to act as a novel and efficient gem-difluoroolefination reagent for both aldehydes and ketones. It was found that the fluorinated sulfinate intermediate in the reaction is relatively stable, which can be observed by 19F NMR and trapped with CH 3l.
- Zhao, Yanchuan,Huang, Weizhou,Zhu, Lingui,Hu, Jinbo
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supporting information; experimental part
p. 1444 - 1447
(2010/06/20)
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- Preparation and 13C NMR study on 1-aryl-3,3-difluoro-2-(phenylethynyl)cyclopropenes: long distance Hammett substituent effect
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Coupling of 1-aryl-3,3-difluoro-2-chlorocyclopropenes and phenylacetylene using Sonogashira reaction with Pd(OAc)2 and CuI as the catalyst with K2CO3 as a base yields phenylethynylcyclopropenes in high selectivity and good yields. The 13C chemical shifts of Cε of ~105 ppm on acetylene group significantly different from phenylacetylene (84 ppm) suggest that the acetylene group possesses less sp hybrid character due to an unusual long distance Hammett substituent effect. It is also confirmed by the substituent parameter analysis, while the Cβ and Cε display the strong resonance effect (their values are 6.89 and 3.37, respectively).
- Lin, Shaw-Tao,Lee, Chuan-Chen,Wu, En-Chien
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p. 5103 - 5106
(2008/09/21)
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- Nucleophilic difluoromethylation and difluoromethylenation using bromodifluoromethyl phenyl sulfone
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Tetrakis(dimethylamino)ethylene (TDAE) was found to be an effective electron-transfer agent that promoted the reactions of bromodifluoromethyl phenyl sulfone with aldehydes to give structurally diverse (benzenesulfonyl) difluoromethylated alcohols in good yield, which can be further transformed into difluoromethyl alcohols and 1,1-difluoro-1-alkenes via reductive desulfonylation and Julia olefination, respectively.
- Surya Prakash,Wang, Ying,Hu, Jinbo,Olah, George A.
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p. 1361 - 1367
(2007/10/03)
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- A novel direct synthesis of (2,2-difluorovinyl)benzenes from aromatic aldehydes
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A novel catalytic approach to (2,2-difluorovinyl)benzenes has been developed. It was found that hydrazones of aromatic aldehydes generated in situ could be converted to the corresponding (2,2-difluorovinyl)benzenes by catalytic olefination reaction (COR) with dibromodifluoromethane in the presence of CuCl.
- Nenajdenko, Valentine G.,Varseev, Georgy N.,Korotchenko, Vasily N.,Shastin, Alexey V.,Balenkova, Elisabeth S.
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p. 115 - 118
(2007/10/03)
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- Proton-Transfer Reactions. 3. Differences in the Protonation of Localized and Delocalized Carbanion Intermediates
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Rates, activation parameters, and product distributions are reported for the reaction of methanolic sodium methoxide with XC6H4CH = CF2 (V) and C6F5CH = CF2 (IX) and compared to previously reported results for C6H5C(CF3) = CF2 (I).A ρ = 3.5 was calculated
- Koch, Heinz F.,Koch, Judith G.,Koch, Nanci H,,Koch, Andrew S.
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p. 2388 - 2393
(2007/10/02)
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