Mechanism of Vinylic and Allylic Carbon−Fluorine Bond Activation of Non-Perfluorinated Olefins Using Cp*2ZrH2
- 27 June 2002
- journal article
- research article
- Published by American Chemical Society (ACS) in Journal of the American Chemical Society
- Vol. 124 (29) , 8681-8689
- https://doi.org/10.1021/ja0125568
Abstract
Cp*2ZrH2 (1) (Cp* = pentamethylcyclopentadienyl) reacts with vinylic carbon−fluorine bonds of CF2CH2 and 1,1-difluoromethylenecyclohexane (CF2C6H10) to afford Cp*2ZrHF (2) and hydrodefluorinated products. Experimental evidence suggests that an insertion/β-fluoride elimination mechanism is occurring. Complex 1 reacts with allylic C−F bonds of the olefins, CH2CHCF3, CH2CHCF2CF2CF2CF3, and CH2C(CF3)2 to give preferentially 2 and CH3−CHCF2, CH3−CHCF−CF2CF2CF3, and CF2C(CF3)(CH3), respectively, by insertion/β-fluoride elimination. In the reactions of 1 with CH2CHCF3 and CH2CHCF2CF2CF2CF3, both primary and secondary alkylzirconium olefin insertion intermediates were observed in the 1H and 19F NMR spectra at low temperature. A deuterium labeling study revealed that more than one olefin-dihydride complex is likely to exist prior to olefin insertion. In the presence of excess 1 and H2, CH2CHCF3 and CH2CHCF2CF2CF2CF3 are reduced to propane and (E)-CH3CH2CFCFCF2CF3, respectively.Keywords
This publication has 25 references indexed in Scilit:
- Aliphatic and Aromatic Carbon−Fluorine Bond Activation with Cp*2ZrH2: Mechanisms of HydrodefluorinationJournal of the American Chemical Society, 2001
- C−D0 (D0 = π-donor, F) Cleavage in H2CCH(D0) by (Cp2ZrHCl)n: Mechanism, Agostic Fluorines, and a Carbene of Zr(IV)Journal of the American Chemical Society, 2001
- Aliphatic Carbon−Fluorine Bond Activation Using (C5Me5)2ZrH2Journal of the American Chemical Society, 2000
- Reaction of Vinyl Chloride with a Prototypical Metallocene Catalyst: Stoichiometric Insertion and β-Cl Elimination Reactions with rac-(EBI)ZrMe+ and Catalytic Dechlorination/Oligomerization to Oligopropylene by rac-(EBI)ZrMe2/MAOJournal of the American Chemical Society, 2000
- Hydrogenolysis of Aliphatic Carbon−Fluorine Bonds in Fluoroalkyl−Iridium Complexes to Give HydrofluorocarbonsJournal of the American Chemical Society, 1999
- Facile Activation of Carbon−Fluorine Bonds in Saturated Fluoroalkyl Ligands by Coordinated Water in Fluoroalkyl Aqua Complexes of RhodiumJournal of the American Chemical Society, 1997
- Group IV Metallocene-Mediated Synthesis of Fluoroaromatics via Selective Defluorination of Saturated PerfluorocarbonsJournal of the American Chemical Society, 1996
- Cobaltocenium Fluoride: A Novel Source of "Naked" Fluoride Formed by Carbon-Fluorine Bond Activation in a Saturated PerfluorocarbonJournal of the American Chemical Society, 1994
- Valence bond isomers of aromatic compounds stabilized by trifluoromethyl groupsAccounts of Chemical Research, 1981
- Hydride-transfer reactions of borine—I: Synthesis of boron-carbon bonds from the fluoroethylenesJournal of Inorganic and Nuclear Chemistry, 1958