Trifluoroacetoxy

Bis-(trifluoroacetoxy)iodobenzene [2712-78-9] M 430.0, m 112-114 (dec), 120-121 , 124-126". Cryst from warm trifluoroacetic acid and dry over NaOH pellets. Recrystd from Me2CO/pet ether. Melting point depends on heating rate. [Synthesis 445 1975.]... 

An interesting development of this research is the preparation of polymer-supported FITS reagent from bis(trifluoroacetoxy)iodoperfluoroalkanes and Nafion-H [145]. FITS-Nafion reacts with organic substrates that react to usual FITS reagents, but the products of the perfluoroalkylation reaction can be separated easily from the insoluble resin by filtration [145]... 

A synthesis for the enantiomerically pure 535 was developed starting with D-phenylalanine which upon reaction with methyl chloroformate gave 528 whose reaction with methoxylamine afforded 529. Cyclization with bis(trifluoroacetoxy)iodobenzene in presence of trifluoroacetic acid gave the tetrahydroquinoline derivative 530 which was demethoxylated to give 531. Treatment of 531 with either benzyl chloroformate or... 

Oxidation of 5//-dibenz[7>,/]azepine (12) with Fremy s salt [ON(S03K)2] yields a mixture of acridine-9-carbaldehyde (13) and 2//-dibenz[A,/]azepin-2-one (14).215 The dibenzazepin-2-one 14 is also obtained in 46% yield with bis(trifluoroacetoxy)pentafluoroiodobenzene [PhI(OCOCF3)2] in acetonitrile as the oxidant.221... 

The mechanism of oxidation probably involves in most cases the initial formation of a glycol (15-35) or cyclic ester,and then further oxidation as in 19-7. In line with the electrophilic attack on the alkene, triple-bonds are more resistant to oxidation than double bonds. Terminal triple-bond compounds can be cleaved to carboxylic acids (RC=CHRCOOH) with thallium(III) nitrate or with [bis(trifluoroacetoxy)iodo]pentafluorobenzene, that is, C6F5l(OCOCF3)2, among other reagents. 

For example, photolysis of a suspension of an arylthallium ditrifluoro-acetate in benzene results in the formation of unsymmetrical biphenyls in high yield (80-90%) and in a high state of purity 152). The results are in full agreement with a free radical pathway which, as suggested above, is initiated by a photochemically induced homolysis of the aryl carbon-thallium bond. Capture of the resulting aryl radical by benzene would lead to the observed unsymmetrical biphenyl, while spontaneous disproportionation of the initially formed Tl(II) species to thallium(I) trifluoroacetate and trifluoroacetoxy radicals, followed by reaction of the latter with aryl radicals, accounts for the very small amounts of aryl trifluoroacetates formed as by-products. This route to unsymmetrical biphenyls thus complements the well-known Wolf and Kharasch procedure involving photolysis of aromatic iodides 171). Since the most versatile route to the latter compounds involves again the intermediacy of arylthallium ditrifluoroacetates (treatment with aqueous potassium iodide) 91), these latter compounds now occupy a central role in controlled biphenyl synthesis. 

We developed a convenient synthesis of 3-cyclopentenyl hydroperoxide via hydro-boration and autoxidation of cyclopentadiene, and bromination proceeded smoothly to afford 32 40). Ring closure with silver trifluoroacetate (Eq. 26) afforded a 5-bromo-2,3-dioxabicyclo[2.2.1]heptane 34 (6%) and a 5-trifluoroacetoxy-2,3-dioxabicyclo-[2.2.1]heptane 35 (14%), and it was shown independently that 34 is rapidly converted into 35 by reaction with Ag02CCF3. To avoid the trifluoroacetate bromide substitution that accompanies and competes with the dioxabicyclization, 32 was treated with silver oxide and this slowly yielded an isomeric 5-bromo-peroxide 33 (42 %) (Eq. 26). 

Interaction to produce 3,5-dimethyl-4-bis(trifluoroacetoxy)iodoisoxazole yields a detonable by-product, believed to be iodine pentaoxide contaminated with organic material. 

Bis (triethylstannyl)acetylene Bis(triethylstannyl) sulphate [57-52-3] Bis(trifluoroacetoxy)dibutylstannane [52112-09-1 ] Bis(trimethylhexyl)dichlorostannane [64011-34-8] Bis(triphenylstannyl) sulphate [3021-41-8]... 

For example, 2-hexanone in MeCN gave 5-acetamino-2-hexanone (44) in 40% yield (Scheme 17) [82], and 2-pentanone was oxidized in trifluoroacetic acid to give a mixture of 4-trifluoroacetoxy-2-pentanone (24%) and 3- and 4-penten-2-one (6%) [83]. A mechanism involving intramolecular hydrogen abstraction by a ketone cation radical that forms a car-benium ion via a [l,5]-hydrogen shift was proposed. 

Synthesis of l,3-dihydro-2,2-bis(trifluoroacetoxy)-benzo[c]tellurophenef A mixture of 2,2-diiodo-l,3-dihydrobenzo[c]tellurophene (4.86 g, 10 mmol) and silver trifluoroacetate (4.42 g, 20 mmol) in benzene (200 mL) was stirred at room temperature for 2 h. After filtration, the fdtrate was concentrated to give l,3-dihydro-2,2-bis(trifluoroacetoxy)-benzo[c]tellnrophene (4.17 g, 91%), m. p. 160°C (dec.). 

Oximes also have been reduced to hydroxylamines with bis(trifluoroacetoxy) borane " and photochemically with PhSetf . 

The synthesis of 1,2,5-oxadiazoles is based on cyclization of l,2-dioximes or a-nitrooxime derivatives. The chemistry of dioximes is reviewed by Kotali and Papageorgiou. Thus, reaction of dioximes 270 with 5% aqueous NaOCl in the presence of NaOH in EtOH afforded l,2,5-oxadiazole-2-oxides 271 in good yields (equation 116) . Bromocyan , N2O4/CH2CI2 , bis(trifluoroacetoxy)iodobenzene and Si02 at 150 were also used as reactants in the cyclization of 1,2-dioximes to 1,2,5-oxadiazoles. 

In addition to the aforementioned syntheses of various carbazole-l,4-quinone alkaloids, many formal syntheses for this class of carbazole alkaloids were also reported. These syntheses involve the oxidation of the appropriate 1- or 4-oxygenated-3-methylcarbazoles using Fremy s salt (potassium nitrosodisulfonate), or PCC (pyridinium chlorochromate), or Phl(OCCXI F3)2 [bis(trifluoroacetoxy)iodo]-benzene. Our iron-mediated formal synthesis of murrayaquinone A (107) was achieved starting from murrayafoline A (7) (see Scheme 5.34). Cleavage of the methyl ether in murrayafoline A (7) and subsequent oxidation of the resulting intermediate hydroxycarbazole with Fremy s salt provided murrayaquinone A (107) (574,632) (Scheme 5.113). 

Addition of methyllithium to the lactone 1219, followed by reduction with sodium borohydride in refluxing ethanol, afforded, almost quantitatively, ellipticine (228). Reaction of the compound 1219 with the lithio derivative of formaldehyde diethylmercaptal, and reduction with sodium borohydride in refluxing ethanol, led to the mercaptal 1221. Cleavage of the mercaptal 1221 with bis(trifluoroacetoxy) iodobenzene [Phl(OCOCF3)2] in aqueous acetonitrile gave the 11-formyl derivative, which was reduced with sodium cyanoborohydride (NaBHsCN) to 12-hydroxyellipticine (232) (710,711) (Scheme 5.202). The same group also reported the synthesis of further pyiido[4,3-fc]carbazole derivatives by condensation of 2-substituted indoles with 3-acetylpyridine (712). 

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