Diane Dickie - Carbon-Centered Strong Bases in Phosphonium Ionic Liquids.

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      Publication Details (including relevant citation   information): Ramnial,Taramatee, Taylor,Stephanie A.,   Bender,Marissa L., Gorodetsky,Brian, Lee,Peter T. K.,   Dickie,Diane A., McCollum,Brett M., Pye,Cory C., Walsby,Charles   J., Clyburne,Jason A. C., J. Org. Chem.,   2008, 73 (3), pp 801-812

      Abstract: Phosphonium ionic liqs. (PhosILs),   most notably tetradecyl(trihexyl)phosphonium decanoate   (PhosIL-C9H19COO), are solvents for bases such as Grignard   reagents, isocyanides, Wittig reagents (phosphoranes), and   N-heterocyclic carbenes (NHCs). The stability of the   organometallic species in PhosIL soln. is anion dependent. Small   bases, such as hydroxide, react with the phosphonium ions and   promote C-H exchange as suggested by D-labeling studies. A method   to dry and purify the ionic liqs. is described and this step is   important for the successful use of basic reagents in PhosIL.   NHCs were generated in PhosIL, and these persistent solns.   catalyze org. transformations such as the benzoin condensation   and the Kumada-Corriu cross-coupling reaction. Phosphoranes were   generated in PhosIL, and their reactivity with various org.   reagents was also tested. Inter-ion contacts involving   tetraalkylphosphonium ions were assessed, and the crystal   structure of [Bu4P][CH3CO2·CH3CO2H] was detd. to aid the   discussion. Decompn. of organometallic compds. may also proceed   through electron-transfer processes that, inter alia, may lead to   decompn. of the IL, and hence the electrochem. of some   representative phosphonium and imidazolium ions was studied. A   radical derived from the electrochem. redn. of an imidazolium ion   was characterized by ESR spectroscopy. [on SciFinder(R)]

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