Tetramethylammonium tetrafluoroborate

Attempts to prepare a bicyclobutane by reductive cydization of cyclobutane-1,3-diones have been unsuccessful [114]. a,o)-Dibenzoylalkanes are reduced at a mercury cathode to cycloalkanediols only when a ring size of 5 or 6 results. These reactions have been achieved using either aqueous ethanolic sodium hydroxide [115] or acetonitrile containing tetramethylammonium tetrafluoroborate [113] as electrolyte. Attempts to extend the process to formation of 7-membered rings lead only to oligomeric materials. 

The exciplexes formed between excited arenes (e.g. phenanthrene, naphthalene, 2,3-dimethylnaphthalene) and the acceptor 1,4-dicyanobenzene in ether solutions containing 1-propylamine are quenched by the addition of tetramethylammonium tetrafluoroborate, and products of addition, (129)-(131), are obtained. The authors suggest that under the relatively non-polar conditions the added salt promotes charge separation in the exciplex so that the amine can attack the arene radical cation. 

TBAH tetrabutylammonium hexafluorophosphate TBAP tetrabutylammonium perchlorate TMAB tetramethylammonium tetrafluoroborate. In comparisons of reduction potentials, the following conversion factors are used E(FeCp2 /FeCp2)=E(NHE) — 0.665=E(SCE) — 0.424=E (Ag/AgNOs)-0.105... 

Figure 16.9 Photo-reduction of protons in Tube 1 and photo-oxidation of water in Tube 2, both starting from an aqueous solution containing a salt composed of weakly hydrophilic ions (tetramethylammonium tetrafluoroborate) and hydrochloric acid.

The reaction of thiopyrylium salts with tetramethylammonium fluoride or AgF yields 2-fluoro-2//-thiopyran together with very minor amounts of 4-fluoro-4//-thiopyran (Equation 111). In like manner, the 2,4,6-tri-/-butyl derivative gives mainly the 2-fluoro compound and bcnzo /( thiopyrylium salts mainly afford 2-fluoro-2//-l-ben-zothiopyran (Equation 112). Both thioxanthylium tetrafluoroborate and the 9-phenyl derivative give the 9-fluoro-thioxanthene. In no reaction was there any evidence of attack of F at sulfur <2003JFC(120)49>. 

Tetrafluoro(perfluorophenyl)silicates, M+ [C6F5SiF4]% obtained by the interaction between trifluoro(perfluorophenyl)silanc and metal fluorides MF (M = K, Cs) or tetramethylam-monium fluoride in nonaqueous acetonitrile or diglyme,169 170 are excellent reagents for penta-fluoroarylation with formation of pentafluoro-substituted derivatives of benzene. Thus, the reaction of these salts with nitrosonium and nitronium tetrafluoroborates leads to per-fluoro(nitrosobenzenc)(14)and perfluoro(nitrobenzene)(15), respectively, in quantitative yield. In the case of reaction with perfluoropyridine, perfluoro(4-phenylpyridine) (16) (33% yield) and pentafluorobenzene (37% yield) arc formed. Reaction of tetramethylammonium tetrafluo-ro(perfluorophenyl)silicate with bromine or iodine pentafluoride gives the corresponding bro-mopentafluorobenzene and pentafluoro(tetrafluoroiodo)benzene.171... 

C2 5H2 sFeNOa, (2-Cyclohexyl-3,5-diphenyl-1-oxo-2-azapenta-(3-5-tj)-enyl-1-yl)tricarbonyliron, 44B, 1131 C2 5H2 ftBFijMnNOaPS, (Dimethylamino(thiomethoxy )carbene) (triphenylphos-phine)tricarbonyImanganese tetrafluoroborate, 42B, 630 C2 5H2 i Cl2N2Pt 0.5 C2H6O, Dichlorobis( 1, 2-diphenylcyclopropane)bis-(pyridine)platinum ethanolate, 39B, 571 C2 5H2 l Fes 20 6 f Tetramethylammonium carbidohexadecacarbonyl-hexaferrate(2-), 40B, 715... 

To benzo[/z]quinolinyl palladium(II) pyridine-sulfonamido complex (128 mg, 0.200 mmol) in MeCN (2.0 mL) at 23 °C was added l-chloromethyl-4-fluoro-l,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate) (77.9 mg, 0.220 mmol). After stirring for 10 min at 23 °C, tetramethylammonium fluoride tetrahydrate (72.6 mg, 0.440 mmol) was added to the reaction mixture. After stirring for 20 min at 23 °C, the precipitate was filtered off and washed with acetone (5x2 mL). The solid was dissolved in CH2CI2 and filtered through a pad of celite. The filtrate was concentrated in vacuo to afford 119 mg of the title compound as an orange solid (88% yield). ... 

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