- Synthesis of the smallest axially chiral molecule by asymmetric carbon-fluorine bond activation
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Enantioselect-DeFluor: Carbon-fluorine bond cleavage by a chiral zirconium complex allows the synthesis of optically active 1,3-difluoroallene for the first time. Its absolute configuration was established by gas-phase vibrational circular dichroism spectroscopy (see picture). Copyright
- Kuehnel, Moritz F.,Schloeder, Tobias,Riedel, Sebastian,Nieto-Ortega, Belen,Ramirez, Francisco J.,Lopez-Navarrete, Juan T.,Casado, Juan,Lentz, Dieter
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- CARBENE CHEMISTRY. PART 13 . PREPARATION OF SOME FLUOROALLENES BY A CARBENE ROUTE, AND THE REACTION OF ALLENES WITH HALOGENOCARBENES
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Fluoroallene and 1,3-difluoroallene are prepared in good overall yield by the addition of dichlorocarbene to vinyl fluoride and 1,2-difluoroethylene respectively, followed by pyrolysis of the dichlorocyclopropanes and treatment of the resulting dichloropropenes with zinc.Pyrolysis of 1,1-dichloro-2-fluorocyclopropane over zinc gives fluoroallene directly.The reaction of allene with 2,2,3-trifluoro-3-trifluoromethyloxiran at 180 deg C as a source of difluorocarbene gives both 1,1-difluoro-2-methylenecyclopropane and its rearrangement product 1-(difluoromethylene)cyclopropane, the latter reacting more readily with a second difluorocarbene to give 2,2,3,3-tetrafluorospiropentane.In an analogous way, fluoroallene reacts with dichlorocarbene, generated from trifluoro(trichloromethyl)silane at 140 deg C, to give E- and Z-1,1-dichloro-2-(fluoromethylene)cyclopropane, 1-(dichloromethylene)-2-fluorocyclopropane, and 2,2,3,3-tetrachloro-4-fluorospiropentane.
- Bunegar, Michael J.,Fields, Roy,Haszeldine, Robert N.
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p. 497 - 510
(2007/10/02)
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