2,2-Diphenyl-1 - trifluoroacetate

The diphenyl-4-pyridylmethyl group is cleaved by Zn/AcOH, 1.5 h, 91% yield H2/Pd-C, 91% yield or by electrolytic reduction, 2.5 h, 0°, 87% yield. The Dppm group is stable to trifluoroacetic acid. " ... 

The bicyclic oxepin 8//-3-oxacyclohept[d]oxepin-8-one dissolved in trifluoroacetic acid undergoes a rearrangement to the expected phenol derivative 1. Substituents in the 2- and/or 7-position of the oxepin part, however, give rise to the formation of l-acylazulen-6-ols 2 by ring contraction.148 The 2,7-diphenyl derivative affords a mixture of l-benzoyl-2-phenylazulen-6-ol (37%), l-benzoyl-2-phenylazulen-6(l//)-one (35%), and 2-phenylazulen-6-ol (23%), which was presumably formed via the azulenone and a shift of the benzoyl substituent to the oxygen. 

It is possible to effect reduction of tertiary benzylic hydroxy functions in the presence of primary halogens. Treatment of 1,1-diphenyl-l-hydroxy-2-haloethanes in chloroform with a slight excess of triethylsilane and a 9- to 10-fold excess of trifluoroacetic acid yields the corresponding 2,2-diphenyl-1-haloethanes (Eq. 45). The yield of the chloride is 77% after one hour at —15°, whereas that of the bromide is 66% following one hour at 0°.184... 

Diphenyl ether undergoes cyclization to dibenzofuran in good yield on treatment with 1-2 mol equiv of palladium(II) acetate in boiling solvents such as acetic acid or trifluoroacetic acid or mixtures of acetic acid and methanesulfonic acid (15 The rate of reaction is greater in the more... 

The acylation of dibenzofuran is carried out under the usual Friedel-Crafts conditions with an acid chloride or an acid anhydride in the presence of aluminum chloride. Dibenzofuran on treatment with 2-trifluoromethane-sulfonyloxypyridine and benzoic acid in boiling trifluoroacetic acid produces the 2-benzoyl derivative in 75% yield. The species responsible for benzoyla-tion is probably a mixed anhydride of trifluoromethanesulfonic acid and benzoic acid. Dibenzofuran on treatment with 2-benzoyloxypyridine and trifluoroacetic acid also produces the 2-benzoyl compound (21%). The kinetics of the acetylation of dibenzofuran with acetyl chloride and aluminum chloride in nitroethane at 25"C have been studied. Only the 2-acetyl compound was detected by the methods used. The rate obtained is in general agreement with the studies mentioned previously. The rate of acetylation of diphenyl ether relative to toluene was 138 (+ 16), whereas that of dibenzofuran was 5.9 ( 0.3). In contrast, the benzoylation of dibenzofuran with benzoyl chloride in the presence of aluminum chloride in nitrobenzene at... 

The protonation of 185 and 186 with trifluoroacetic acid (TFA) gave 4-(/i t/-butylthio)-3,6-diphenyl- 193 and 4-(ter1-butylthio)-3,6-di(2-thienyl)thieno[3,4-f]thiophene-l(3//)-thione 194 (Scheme 18). The treatment of 193 with sodium hydride and then isopropyl iodide led to 4-(/i< t/-butylthio)-3,6-diphenyl-l-(isopropylthio)thieno[3,4-f]thio-phene 195 by the regeneration of the thieno[3,4-f]thiophene ring system, thus making possible the synthesis of other alkylthio-substituted thieno[3,4-(r]thiophene derivatives. When the reaction of 185 with TFA was carried out... 

Prakash, Olah, and co-workers256 have prepared Mosher s acid analogs by the hydroxyalkylation of substituted benzenes with ethyl trifluoropyruvate [Eq. (5.95)]. Deactivated aromatics (fluorobenzene, chlorobenzene) required the use of excess triflic acid indicative of superelectrophilic activation.3 5 In contrast to these observations, Shudo and co-workers257 reported the formation gem-diphenyl-substituted ketones in the alkylation of benzene with 1,2-dicarbonyl compounds [Eq. (5.96)]. In weak acidic medium (6% trifluoroacetic acid-94% triflic acid), practically no reaction takes place. With increasing acidity the reaction accelerates and complete conversion is achieved in pure triflic acid, indicating the involvement of diprotonated intermediates. 

Of derivatives of the 1,3-ditelluroles, only the ditellurafulvenes 2 are known. Their first representatives, cis- and f rans-2,6-diphenyl-1,4-ditellur-afulvenes 2 were obtained in 12% total yield along with fran.s-2,4-benzyli-dene-l,3-ditelluretane la when sodium phenylethynyltellurolate was treated with trifluoroacetic acid in ether (81CC828) (see Section II). 

The PPS yield depends on the acidity of the mixture. The oxidative polymerization does not proceed in the absence of acids. Strong acids, such as triflu-oromethanesulfonic acid and trifluoroacetic acid, are required for the VO-cata-lyzed polymerization. The oxidative polymerization of diphenyl disulfide is facilitated by the activated VO(acac)2 produced by the acid. Diphenyl disulfide is not oxidized by 02 only or an equimolar amount of VO(acac)2 in the absence of acid. The VO catalyst is estimated to be an excellent electron mediator, through activation by acids, to promote the electron transfer between diphenyl disulfide and molecular oxygen. 

C-(w-propyl)-N-phenylnitrone to N-phenylmaleimide, 46, 96 semicarbazide hydrochloride to ami-noacetone hydrochloride, 45,1 tetraphenylcyclopentadienone to diphenyl acetylene, 46, 44 Alcohols, synthesis of equatorial, 47, 19 Aldehydes, aromatic, synthesis of, 47,1 /8-chloro-og3-unsaturated, from ketones and dimethylformamide-phosphorus oxychloride, 46, 20 from alkyl halides, 47, 97 from oxidation of alcohols with dimethyl sulfoxide, dicyclohexyl carbodiimide, and pyridinium trifluoroacetate, 47, 27 Alkylation, of 2-carbomethoxycyclo-pentanone with benzyl chloride, 45, 7... 

Diphenyl tellurium bis[trifluoroacetate] reacted under the same conditions with tetrame-thylurea, sulfoxides, triphenylphosphane oxide and sulfide, triphenylarsane oxide, pyridine 1-oxides, tetramethylpiperidine, benzimidazole, morpholine, and 7V,Ar-diphenylthiourea to give 1 1 complexes as sharp-melting, colorless solids that are soluble in common organic solvents3. 

Diphenyl Tellurium Trifluoroacctate 2-Formylphenoxidel A solution of 2.28 g (20 mmol) trifluoroacetic acid in 50 ml diethyl etheris added to a solution of 5.23 g (10 mmol) of diphenyl tellurium bis[2-formylphenoxide] in 50 ml diethyl ether. The mixture is stirred for 2 hand then kept overnight in a deep-freezer. The crystals are collected by filtration and washed with petroleum ether (40-60°) m.p. 110°. 

Diphenyl Tellurium Trifluoracetate 8-Quinolinoxide2 A mixture of 1.14 g (10 mmol) trifluoroacetic acid, 5.45 g (10 mmol) diphenyl tellurium dioxinate, and 20 m/ dry benzene is refluxed for 4h. The mixture is concentrated and the concentrate mixed with an excess of diethyl ether to precipitate the product m.p. 170°. 

Bis[diphenyl tellurium acetate oxide was obtained in 64% yield when equimolar amounts of diphenyl tellurium oxide and diphenyl tellurium diacetate were refluxed in benzene2. The corresponding trifluoroacetate was prepared with methanol as the reaction medium3 at 20°. 

The trifluoroacetate was obtained as the hemihydrate upon slow evaporation of the methanol from a methanolic solution containing diphenyl tellurium oxide (2.5 mmol) and trilluoroacetic acid (5 inmol)3. 

The Step 3 product (324.7 g) and 4400 ml EtOAc were heated until dissolution then treated with 2,2-diphenyl ethanal (164.7 g), trimethyl orthoacetate (100.8 g), and trifluoroacetic acid (4.35 g). The mixture was stirred 3 days at ambient temperature... 

Another example of the simultaneous addition of fluorine and oxygen to a C = C bond is the fluorination of diphenylacetylene with xenon difluoride in the presence of trifluoroacetic acid ° how ever, the yield of the desired l-fluoro-l,2-diphenyl-2-(trifluoroacetoxy)ethene is only 3%, so there is no preparative use for this method. 

Lactonization, 93, 100, 370, 385-386, 413, 423,441,478-479,512 Lasiodiplodin, 386 Lead carbonate, 265 Lead tetraacetate, 199, 265-269 Lead tetrakistrifluoroacetate, 142, 143 Lead(lV) trifluoroacetate-Diphenyl disulfide, 269-270... 

OL-Hydroxysulfenylation. Lead tetraacetate and trifluoroacetic acid form lead(IV) trifluoroacetate in situ When an olefin and diphenyl disulfide are added to this reagent at 0 or -40°, a 3-trifluoroacetoxy sulfide is formed, which on basic work-up generates a thiohydrin (equation I). The reaction involves trans-addition. 

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