Iron -, tetrafluoroborate

Treatment with HBF4 in CHCI3 liberates the thiol and returns the derivatizing agent, [(T7- C6H7)Fe(CO)3] BF4 [tricarbonyl[l,2,3,4,5-77]-2,4-cyclohexadien-l-yl-iron(]+) tetrafluoroborate] as a precipitate. ... 

The iron-mediated construction of the carbazole framework proceeds via consecutive C-C and C-N bond formation as key steps [70,71]. The C-C bond formation is achieved by electrophilic substitution of the arylamine with a tricarbonyliron-coordinated cyclohexadienyl cation. The parent iron complex salt for electrophilic substitutions, tricarbonyl[/j -cyclohexadienylium] iron tetrafluoroborate 6a, is readily available by azadiene-catalyzed complexation and subsequent hydride abstraction (Scheme 9). 

Experimental Procedure 3.1.2. Preparation of an Iron Vinylidene Complex by Electrophilic Abstraction CarbonyUrj -cyclopentadienyOldimethylvinylidene)-(triphenylphosphine)iron tetrafluoroborate [464J... 

Dicarbonyl(cyclopentadienyl) (ethyl vinyl ether)iron tetrafluoroborate Iron(l+), dicarbonyl (n -2,4-cyclopentadien-l-yl )[(l,2-Ti)-ethoxyethene]-, tetrafluoroborate(l-) (10) (75182-42-2)... 

Dicarbonyl(cyclopentadienyl)(trans-3-methyl-2-vinylcyclohexanone)iron tetrafluoroborate, 66, 97... 

Dicarbonyl(cyclopentadienyl)thiophene [Fe(CO)2(C4H4S)(r] -C5H5)][BF4] iron tetrafluoroborate 73... 

Dicarbonyl(cyclopeiitadienyl)[(diinethylsulfoniuin)methyl]iron tetrafluoroborate. 13, 98 15, 117... 

Starting material for this synthetic strategy is tricarbonyl(ri -cyclohexadieny-lium)iron tetrafluoroborate 30, which can be prepared from cyclohexa-1,3-diene (33) and pentacarbonyliron in two steps [74, 75]. Using catalytic amounts of a... 

Scheme 11 Preparation of tricarbonyl(r -cyclohexadienylium)iron tetrafluoroborate (30)...

Dicarbonyl(cyclopentadienyl)[(dimethyl-sulfonium) methyl] iron Tetrafluoroborate ... 

Dlcarbonyl(cyclopentadlenyl) [(dimethylsulfonlum) methyl] -Iron Tetrafluoroborate, 198 C10H13F3O3SSI... 

C33H3COb02 , 1,6-BisUricobalt nonacarbonyl)-2,3-(dicobalt hexacar-bonyl)hexa-4-yne - benzene, 35B, 505 C3 3H2 eBF4Fe02P, (1-Triphenylphosphonium-2-phenyl-vinyl)-(T -cyclo-pentadienyl)dicarbonyl iron tetrafluoroborate, 45B, 890 C3 3H2 7F6O4PRU, 7 -Cyclopentadienyl (1, 3,4-17- (1, 2-dimethoxycarbonyl-5,5,5-trifluoro-3-trifluoromethylpent-1,3-dienyl))triphenylphos-phineruthenium, 42B,. 637... 

CleHisBF,Fe20,S, M Ethylthio-bis(dicarbonyl(T -cyclopentadienyl)iron) tetrafluoroborate, 44B, 756... 

Disconnect the nitrogen supply and transfer the mixture to a clean singlenecked round-bottomed flask (250 mL) with the aid of a funnel. Wash out the reaction flask with an additional 10 mL of dry dichloromethane. Reduce the volume of the solvent to about 10 mL on a rotary evaporator before adding wet diethyl ether (50 mL) to precipitate tricarbonyl(4-methoxy-1-methylcyclohexadienylium)iron tetrafluoroborate. (If an oil is formed at this point, vigorous swirling and/or scratching the inside of the flask with a spatula... 

A solution of 4-[(2 )-(2-acetoxypropyl)]-5-amino-l,2-dimethoxy-3-methylbenzene (1.96 g, 7.33 mmol) and tricarbonyl(ri -cyclohexadienylium)iron tetrafluoroborate (1.12 g, 3.66 mmol) in acetonitrile (30 mL) was stirred at room temperature for 9 days in air. A saturated aqueous solution of sodium hydrogen carbonate (20 mL) was added to the reaction mixture and the aqueous layer was extracted with ethyl acetate (3 x 20 mL). The combined organic layers were washed with water (2 x 20 mL) and dried with sodium sulfate. After removal of the solvent, the residue was subjected to flash chromatography (hexane/ethyl acetate/triethylamine, 8 2 1) on silica gel to afford the tricarbonyl(il -4a,9a-dihydrocarbazole)iron complex as a bright yellow viscous liquid [a]n = -13.0 (c = 0.5, CHCI3) 1.67g(94%). ... 

Tricarbonyl(Ti -cyclohexadienylium)iron tetrafluoroborate was described first by Fischer in 1960. The required tricarbonyl(T -cyclohexadiene)iron complex can be conveniently obtained in high yield from cyclohexa-1,3-diene and pentacarbonyliron using catalytic amounts of a 1-azabuta-1,3-diene (see Section 2.5.1). Hydride abstraction from the tricarbonyl(ri -cyclohexadiene)iron complex using triphenylmethyl tetrafluoroborate affords the Ti -dienyliumiron complex salt almost quantitatively (Scheme 4-1... 

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