Chloro tetrafluoroborate

Sodium P-chloroethanesulfonate [15484-44-3] can be obtained by reacting vinyl chloride with sodium bisulfite [7631-90-5] (66). Reaction with nitronium tetrafluoroborate [13826-86-3] yi ds l-chloro-l- uoro-2-nitroethane [461-70-1] (67). 

Haloisoxazolium salts were treated with Na2S to produce the above titled compounds (76ZC270). For example, 5-chloro-2-methyl-3-phenylisoxazolium tetrafluoroborate and Na2S gave 2-methyl-3-phenyl-3-isoxazoline-5-thione. 

Benzoxazolium tetrafluoroborate, 2-chloro-3-ethyl-as dehydrating agent, 1, 447 Benzoxazolone, N-phenyl-synthesis, 6, 223 Benzoxazolones alkylation, 6, 201 hydrolysis, 6, 203 reactions... 

Chloro-3,4-dimethylthiazolium tetrafluoroborate with [Cr(CO)5] yields the neutral carbene complex 7 (74JCS(D)760). 

Chloro-3,4-dimethylthiazolium tetrafluoroborate reacts with [Fe(CO)4] to yield the neutral carbene complex 22 (74JCS(D)760). l-Methyl-2-chlorobenzothiazolium tetrafluoroborate with Na2[Fe(CO)4] dioxane gives the similar neutral carbene complex (75JCS(D)939). 

Chloro-3,4-dimethylthiazolium tetrafluoroborate and 3-methyl-2-chlor-obenzothiazolium tetrafluoroborate and [Os3(CO)i2] in the presence of sodium in liquid ammonia give the neutral carbene complexes 37 and... 

On the basis of these redox potentials it seems likely that direct electron release to the benzenediazonium ion takes place only with iodide. This corresponds well with experience in organic synthesis iodo-de-diazoniations are possible without catalysts, light, or other special procedures (Sec. 10.6). For bromo- and chloro-de-di-azoniations, catalysis by cuprous salts (Sandmeyer reaction, Sec. 10.5) is necessary. For fluorination the Balz-Schiemann reaction of arenediazonium tetrafluoroborates in the solid state (thermolysis) or in special solvents must be chosen (see Sec. 10.4). With astatide (211At-), the heaviest of the halide ions, Meyer et al. (1979) found higher yields for astato-de-diazoniation than for iodo-de-diazoniation, a result consistent with the position of At in the Periodic System. It has to be emphasized, however, that in investigations based on measuring yields of final products (Ar-Hal), the possibility that part of the yield may be due to heterolytic dediazoniation is very difficult to quantify. 

Table 10-1 also includes the experimental results of Daasbjerg and Lund (1992) on the chloro-de-diazoniation of benzenediazonium tetrafluoroborate in tetrachloro-methane/acetonitrile (3 1) in the presence of FeCl3/FeCl2 (4 3). The reported yield is surprisingly high. 

Lipases from C. antarctica and P. cepacia showed higher enantioselectivity in the two ionic liquids l-ethyl-3-methylimidazolium tetrafluoroborate and l-butyl-3-methylimidazolium hexafluoroborate than in THE and toluene, in the kinetic resolution of several secondary alcohols [49]. Similarly, with lipases from Pseudomonas species and Alcaligenes species, increased enantioselectivity was observed in the resolution of 1 -phenylethanol in several ionic liquids as compared to methyl tert-butyl ether [50]. Another study has demonstrated that lipase from Candida rugosa is at least 100% more selective in l-butyl-3-methylimidazolium hexafluoroborate and l-octyl-3-nonylimidazolium hexafluorophosphate than in n-hexane, in the resolution of racemic 2-chloro-propanoic acid [51]. 

Nitryl chloride (NO2CI) also adds to alkenes, to give p-halo nitro compounds, but this is a free-radical process. The NO2 goes to the less-substituted carbon. Nitryl chloride also adds to triple bonds to give the expected l-nitro-2-chloro alkenes. The compound FNO2 can be added to alkenes by treatment with HF in HNOa or by addition of the alkene to a solution of nitronium tetrafluoroborate (NOJBF4, see 11-2) in 70% polyhydrogen fluoride-pyridine solution (see also 15-37). 

Scheme 2 shows the preparation of carbene complexes starting from [L M-ER3]" = [MeCp(CO)2Mn-SiMePlt2] and [(7r-arene)(CO)2Cr-SnPh3] [12,13]. By a related approach, a cationic cyclopropenylidene complex was prepared by reaction of Cp(CO)2FeSiMe3 with l-chloro-2,3-diphenylcyclopropenylium tetrafluoroborate [14],... 

Several interesting reactions have been described for quinolizine-3-diazonium tetrafluoroborate 121. Thus, its treatment with secondary amines gave the corresponding triazenes 122 <2004ZNB380>, while its reaction with 1,3-dicarbonyl compounds gave the corresponding hydrazones. In the case of alkyl 4-chloro-3-oxobutanoates, the intermediate hydrazone 123 furnished a pyrazole derivative 124, as shown in Scheme 17 <2002H(57)2091>. 

In an early example, Mukaiyama and coworkers used hetaryl onium salts for nucleoside synthesis. The active hetaryl onium salt is generated in situ from the reaction of 2-chloro-3-ethylbenzoxazolium tetrafluoroborate 77 and the glycosyl acceptor. With benzimidazole as glycosyl acceptor, the resulting 2-(l-benzimida-zoyl)benzoxazolium tetrafluoroborate 78 was obtained. The reaction between the hetaryl onium salt 78 and hemiacetal donor 1 occurs at 60 °C to activate the hemiacetal and thereby reveal the glycosyl acceptor. This procedure led to the formation of nucleoside 80 with exclusive 1,2-trans selectivity [139]. The nucleoside 81 was similarly prepared. Alternatively, 2-fluoro-l-methylpyridinium tosylate 79 directly... 

Silver tetrafluoroborate in ether or toluene has also been used for the synthesis of glycosyl fluorides. Peracetylated 2-chloro-2-deoxy-D-gluco- and -mannopyranosyl fluorides have been prepared by treatment of the corresponding chlorides with the aforementioned reagent.50,51 Products of kinetic control were obtained when diethyl ether was used as the solvent, whereas products of thermodynamic control were obtained when toluene was used instead. Peracetylated... 

Sulfonium, cyclopropyldiphenyl tetrafluoroborate, 54, 28 Sulfonium salts, acetylenic, furans from, 53, 3 Sulfonium ylides, 54, 32 Sulfur, reaction with organo-lithium compounds, 50, 105 Sulfuryl chloride, with 1,1-cyclobutanedicarboxylic acid to give 3-chloro-l,1-cyclobutanedicarboxylic acid, 51, 73... 

Azidomethylbenzenediazonium tetrafluoroborate, 2708 Benzenediazonium tetrafluoroborate, 2223 2-Chloro-3-pyridinediazonium tetrafluoroborate, 1816 5-(4-Diazoniobenzenesulfonamido)thiazole tetrafluoroborate, 3119 5,6-Diphenyl-l,2,4-triazine-3-diazonium tetrafluoroborate 2-oxide, 3677... 

The AgBp4 method was extended to cyclizations onto the alkoxyl side chain. Novel heterocycles A-acyl-3,4-dihydro-lP -2,l-benzoxazines (25) and A-acyl-4,5-dihydro-l//,3//-2,1-benzoxazepines (26) were synthesized by the treatment of open-chain A-chloro-A-(2-phenylethyloxy)- and A-chloro-A-(3-phenylpropyloxy)amides (24, n = 2, 3) with silver tetrafluoroborate in benzene (Scheme 2). Optimal yields of 25 were ultimately obtained with AgBp4 in ether or TPIP. ... 

Dibenz[f ,e]azepine-6,11 -dione and phosphorus pentachloride yield the 6-chloro derivative, ethanolysis of which furnishes the non-planar azatropone (129), identical to the product formed by ethylation of the dione with triethyloxonium tetrafluoroborate (72AJC2421). 

As a consequence of the cyclobutyl to homoallyl rearrangement, reactions of 1-chloro-, 1-bro-mo-l,2-dimethylcyclobutane, 1-chloro- or l-bromo-l,3-dimethylcyclobutane with silver(I) te-trafluoroborate in diethyl ether gave in each case the same open-chain compound 2-fluoro-4-mcthylpent-4-ene (14) as the major product. Thus, l-bromo-l,3-dimethylcyclobutane (13) was treated with silver(l) tetrafluoroborate in diethyl ether at 0 >C to give 2-fluoro-4-methylpent-4-ene (14).22... 

BAu,F4OP,C44H4s, Gold(I-t-), p,-oxo-[tris-(triphenylphosphine)]-tetrafluoroborate( 1 -), 26 326 BClF4IrN2P2C1(,H3 Iridium(III), chloro-(dinitrogen) hydridoj tetrafluoro-borato(l - )]bis(triphenylphos-phine)-, 26 119... 

Chloro- and bromophenols and A -acylhaloanilines can be fluorinated in the ortho or para position by 1-fluoropyridinium triflates and the fluorophenols and iV-acylfluorohaloanilines thus obtained reduced to fluorophenols and iV-acylfluoroanilincs. For example, 4-chlorophenol reacts with 2-chloro-l-fluoro-6-(trichloromethyl)pyridinium tetrafluoroborate in 1,2-dichlo-roethane at 45°C for three hours to give 4-chloro-2-fluorophenol in 68% yield.51... 

Like thallium(I) fluoride (see Section 18.2.), silver(I) tetrafluoroborate is used to convert chloro-formates into the corresponding fluoroformates, which are decomposed to the fluorides as described in Section 16.1.2. Phenyl fluoroformate (4) is obtained in moderate yield in this way from 3.68... 

Silver(I) tetrafluoroborate converts a-bromo-substituted ketones, e.g. 7, to the corresponding fluoro-substituted ketones, e. g. 8, under anhydrous conditions.69 Attempts to convert the a-chloro-substituted ketenes under the same conditions failed.69... 

Trialkyl- or triaryl-1,l-difluoro-25-phosphorines can be prepared by treating the chloro or bromo derivatives with silver(I) tetrafluoroborate.75... 

Chloro- or bromocyclopentadienyl complexes of titanium and zirconium react with silver(I) tetrafluoroborate to form the corresponding fluoro complexes.81 Other complexes yielded the tetrafluoroborates. 

When performing the decomposition of diazonium tetrafluoroborates stabilized by nitro or chloro groups, in aromatic solvents (1,2-dichlorobenzene, nitrobenzene, chloronaphthalene), arylation of the solvent is observed.137... 

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