Trichloromethyl fluoride, reaction

Trichloroacetyl fluoride, 45, 6 2-(Trichloromethyl)bicyclo[3.3.0]octane, from reaction of chloroform and cib,o i-l,5-cyclooctadiene, 47,10 hydrolysis with phosphoric acid to c.ro-m-bicyclo[3.3.0]octane-2-carboxylic acid, 47, 11 1,1,3-Trichloro- -nonane, 46,104 Tricyclo[2.2.1,02 6]heptan-3-ol, 46,... 

Trichloromethyl groups linked to an ether oxygen have high reactivity towards hydrogen fluoride. Thus, complete Cl-F replacement is achieved by heating the reactants in an autoclave, e.g. reaction of 5226 (see also Houben-Weyl, Vol. E4, pp 627-628). 

Kinetically controlled conditions favor the formation of mixed fluorinated compounds if per-halo derivatives are fluorinated with hydrogen fluoride. Therefore, catalysts or coreagents are used to overcome this problem. Thus, selective fluorination of l,3-bis(trichloromethyl)benzene cannot be achieved by hydrogen fluoride using variations in temperature, pressure or time.247 However, if antimony(V) fluoride is added to hydrogen fluoride the reaction produces l-(tri-chloromethyl)-3-(trifluoromethyl)benzene. Selective fluorination can also be performed in compounds with different substitution patterns.247,251 253... 

Aluminum trichloride and boron trifluoride as additives have a similar effect on the fluorination of (trichloromethyl)benzene by antimony(III) fluoride. With the additives, the reaction starts even at O C but no exchange is observed in the absence of the catalysts.12 The relative exchange reactivity order of the antimony halides is as follows antimony(III) fluoride < anti-mony(III) fluoride + antimony/V) chloride < antimony(V) dichlorotrifluoride, antimony/V) di-bromotrifluoride < antimony/V) fluoride.3... 

Chlorine atoms in (trichloromethyl)benzenes which have fluoro, chloro, dichloromethyl, chloroformyl, cyano, isocyanato, jV-phthalimino or methyl substituents in the ring are substituted by fluorine using antimony(III) fluoride (Swarts reaction).3 4 2-(Trifluoromethyl)phen-yl isocyanate, 4-chloro-2-(trifluoromethyl)phenyl isocyanate, 2,4- and 2,5-bis(trifluoro-methyl)phenyl isocyanate, and 2,4-bis(trifluoromethyl)-l,5-phenylenc diisocyanate can be obtained in this way.5... 

The reaction of 5-substituted l.l,3.3-tetrachloro-1.3-dihydroisoben7.ofui ans (R = H, MeO, halogen) with antimony(lll) fluoride is accompanied by partial isomerization of the starting substrates into 2-(trichloromethyl)-5-substituted benzoyl chlorides followed by fluorination of the cyclic and acyclic compounds. No such isomerization is observed when 1,1,3.3-tetrachloro-... 

Other catalysts used in fluorinations with antimony(III) fluoride are boron trifluoride and aluminum trichloride. The reaction of (trichloromethyl)benzene with antimony(III) fluoride and catalytic amounts of aluminum trichloride at 0 X gives mainly (dichlorofluoromethyl)ben-zene and a little (chlorodifluoromethyl)benzene. With greater amounts of aluminum trichloride, the major product is (chlorodifluoromethyl)benzene, bp 142 C.81... 

The trichloromethyl group in 4-chIoro-8-methyl-2-(trichloromethyl)quinoline is completely fluorinated with antimony(V) fluoride/antimony(V) chloride when the reaction is carried out in dichloromethane at — 5 to 0 C and then at room temperature for 48 hours to give 4-chloro-8-methyI-2-(trifluoromethyI)quinoIine in 68% yield.4,3... 

The relative fluorination activity of the aromatic antimony(V) fluorides can be judged by comparing the products of their reaction with (trichloromethyl)benzene conducted in l-2mL of dichloromethane for 2 hours at a fluorinating agcnl/substrate ratio of 1 -1.2 1 (Table 4).104... 

Phenylmercury(II) fluoride-hydrogen fluoride complex fluorinates phenyl(tribromo-methyl)mereury in 60-65% yield when the reaction is carried out in the presence of 48% hydrogen fluoride. Phenyl(trichloromethyl)mercury can be fluorinated to the trifluoromethyl derivative in this manner, but a reaction temperature of 90 C is required. Partial fluorination of (bromodichloromethyl)phcnylmcrcury to (dichlorofluoromethyl)phenylmercury in 60% yield can be achieved at room temperature, but attempted partial fluorination of phenyl(tri-bromomethyl)mercury, (dibromochloromethyl)phenylmercury, and (dibromofluoromethyl)-phenylmereury was unsuccessful phenyl(trifluoromethyl)mercury is the major product obtained.61... 

The complete replacement of the chlorine atoms in (trichloromethyl)benzene by fluorine to give (trifluoromethyl)bcnzene is possible under mild conditions. This transformation can be achieved with a variety of reagents with anhydrous hydrogen fluoride the reagent of choice due to cost and the lack of side reactions. "Substituted (trichloromethyl)benzenes are successfully transformed into the corresponding (trifluoronicthyl)benzenes 1-3 by hydrogen fluoride in the presence of a catalytic amount of antimony(V) chloride.A procedure is given for the formation of 1-(dichloromethyl)-2-(trifluoromethyl)benzene (4). ... 

The fluorination of an aromatic trichloromethyl group is also achieved with antimony(III) fluoride in molar ratios ranging from antimony(III) fluoride/(trichloromcthyl)benzene 5 1 to 2. j 129 ms -phis chemistry (the Swarts reaction) has been extended to substituted aromatics, with some examples given by the formation of 7,136 8,137 9138 and 10.139... 

Synthesis of 1-Chlorocyclopropene. Vinyltrimethylsilane Serves as a useful precursor to 1-chlorocyclopropene (14). action of the vinylsilane with phenyl(trichloromethyl) Bercury 7 in refluxing benzene followed by fluoride-induced lirnination of TMSCl from the cyclopropane (13) furnishes 1-chlorocyclopropene in good yield, as evidenced in the subsequent l iels-Alder reaction with 1,3-diphenylisobenzylfuran (eq 7). previous synthesis of 1-chlorocyclopropene gave only 5"10% yield. 

Qiloroform yields both the trichloromethyl anion and dichlorocarbene as reactive intermediates under basic phase transfer conditions. The trichloromethyl anion reacts with phenylmercuric chloride under these conditions to yield phenyl(trichloromethyl)-mercury (72%). The product is unstable, however, to the 50% aqueous sodium hydroxide solution usually used in phase transfer catalysis. When 10—15% aqueous sodium hydroxide solution was used, while maintaining the ionic strength by addition of potassium fluoride, the product survived. Reasonable yields of the mercury compound were thus obtained and the reaction was successfully extended to bromodichloromethane [yielding 64% of phenyl(bromodichloromethyl)mercury] and bromoform [yielding phenyl(tribromomethyl)mercury, 54%]. The transformation is illustrated in equation 3.18 [26]. 

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