- Rhodium Catalyzed Regioselective C?H Allylation of Simple Arenes via C?C Bond Activation of Gem-difluorinated Cyclopropanes
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Herein, we report a rhodium catalyzed directing-group free regioselective C?H allylation of simple arenes. Readily available gem-difluorinated cyclopropanes can be employed as highly reactive allyl surrogates via a sequence of C?C and C?F bond activation, providing allyl arene derivatives in good yields with high regioselectivity under mild conditions. The robust methodology enables facile late-stage functionalization of complex bioactive molecules. The high efficiency of this reaction is also demonstrated by the high turnover number (TON, up to 1700) of the rhodium catalyst on gram-scale experiments. Preliminary success on kinetic resolution of this transformation is achieved, providing a promising access to enantio-enriched gem-difluorinated cyclopropanes.
- Jiang, Zhong-Tao,Huang, Jiangkun,Zeng, Yaxin,Hu, Fangdong,Xia, Ying
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supporting information
p. 10626 - 10631
(2021/04/05)
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- Ring-Opening Functionalization of Simple gem-Difluorocyclopropanes by Single-Electron Oxidants
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It was reported for the first time that single-electron oxidants such as CAN or K2S2O8 affected facile ring opening of simple gem-difluorocyclopropanes to afford 1,3-dibromo-2,2-difluoropropanes in good yields by the action of KBr, and the appropriate choice of conditions allowed to incorporate not only second halogen atoms but also hydroxy or acetamido groups at the C1 position in the difluoropropane structures in a regiospecific fashion after initiation of the reaction by the introduction of the first bromine atom at the C3 position. ?
- Goto, Toshihito,Kawasaki-Takasuka, Tomoko,Yamazaki, Takashi
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p. 9509 - 9518
(2019/08/26)
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- DIFLUOROMETHYLENE COMPOUND AND PRODUCTION METHOD THEREOF
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PROBLEM TO BE SOLVED: To provide a difluoromethylene compound useful as a synthetic intermediate of medical and agricultural chemicals and functional materials; and a production method thereof. SOLUTION: The invention provides: a fluorine-containing compound represented by the specified general formula (1); and a production method of the fluorine-containing compound by opening the ring of a difluorocyclopropane represented by the specified general formula (2) in a solvent in the presence of a reagent for introducing X1 and a reagent for introducing X2. SELECTED DRAWING: None COPYRIGHT: (C)2018,JPOandINPIT
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Paragraph 0089; 0090; 0091; 0092
(2018/10/16)
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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
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Paragraph 0267-0269
(2018/01/11)
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- An improved method for difluorocyclopropanation of alkenes
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Difluorocyclopropanation of alkenes using fluorinated acetate salts using convential heating is often a slow, inefficient, and energy-intensive process. We report here a modified protocol which enables the rapid (5 min) preparation of 1,1-difluorocyclopropanes, using microwave irradiation. The new procedure is not only considerably faster than previously reported methods, but it also employs easily removed, low boiling-point solvents and avoids the use of highly toxic or ozone-depleting substances. Georg Thieme Verlag Stuttgart. New York.
- Gill, Duncan M.,McLay, Neil,Waring, Michael J.,Wilkinson, Christopher T.,Sweeney, Joseph B.
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p. 1756 - 1758
(2014/08/05)
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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 of gem-difluorinated cyclopropanes and cyclopropenes: Trifluoromethyltrimethylsilane as a difluorocarbene source
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Highly versatile: The Ruppert-Prakash reagent (Me3SiCF 3) can be an efficient source of difluorocarbene. By varying the nonmetallic initiator that is used (F- at lower temperatures and I- at higher temperatures), a range of structurally diverse alkenes and alkynes can be converted into the corresponding gem-difluorinated cyclopropanes and cyclopropenes in good yields (see scheme). Copyright
- Wang, Fei,Luo, Tao,Hu, Jinbo,Wang, Ying,Krishnan, Hema S.,Jog, Parag V.,Ganesh, Somesh K.,Prakash, G. K. Surya,Olah, George A.
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supporting information; scheme or table
p. 7153 - 7157
(2011/09/12)
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- Chloride ion-catalyzed generation of difluorocarbene for efficient preparation of gem-difluorinated cyclopropenes and cyclopropanes
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A chloride ion-catalyzed generation of difluorocarbene from a relatively non-toxic and inexpensive precursor, Me3SiCF2Cl (1), under mild and neutral conditions leads to an efficient preparation of gem-difluorocyclopropenes and difluorocyclopropanes through [2 + 1] cycloaddition reactions with alkynes and alkenes, respectively.
- Wang, Fei,Zhang, Wei,Zhu, Jieming,Li, Huaifeng,Huang, Kuo-Wei,Hu, Jinbo
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supporting information; experimental part
p. 2411 - 2413
(2011/04/15)
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