Bistrifluoroacetate

Scheme 59). If phenyliodoso bistrifluoroacetate is used as the oxidizing agent the major product is an isoxazoloisoxazole, but pyridazine 1,2-dioxides are formed in minor amounts together with other products. With lead tetraacetate, in general, pyridazine 1,2-dioxides are the major products. 

Iodosobenzene bistrifluoroacetate is a versatile mild oxidant that has been used to oxidize a broad range of organic compounds, such as alkenes, alkynes, carbonyl compounds, and alcohols Its application in organic synthesis has been summarized m several recent reviews devoted to polyvalent iodine compounds [63, 64, 65]... 

A remarkable dual way to obtain PhI(02CCF3)0I(02CCF3)Ph involved either solvolysis of iodosylbenzene by trifluoroacetic acid or nucleophilic attack by a strong base to the carbonyl group of [bis(trifluoroacetoxy)iodo]benzene [49]. Another unusual reaction leading to the formation of the same iodane has been reported between iodobenzene and xenon bistrifluoroacetate [50]. 

Asymmetric hydrogenation of allylic alcohols (14, 39-40).1 Mammalian dol-ichols (2) are terminal dihydropolyisoprenols which are involved in glycoprotein synthesis. They contain one terminal chiral primary allylic alcohol group. The polyprenols 3 present in plants correspond to dolichols except that they lack the terminal double bond considered to be (Z). They can be obtained by hydrogenation of 2 catalyzed by (bistrifluoroacetate)ruthenium(II) and (S)-l, which affects only the terminal double bond to provide (S)-3 in >95% ee. 

The availability of a-dioximes, which makes them the most common source of furazans also accounts for their widespread use in furoxan preparations. Divers oxidizing agents have been employed, including alkaline hypohalites, potassium ferricyanide, lead tetraacetate, oxides of nitrogen, cerium(IV) ion, AModosuccinimide (80H(14)1279), and phenyl-iodine(III) bistrifluoroacetate. Electrochemical oxidation has also been reported. 

The treatment of isatin with sodium hypochlorite in acetic acid leads to 1-chloroisatin, an effective mild oxidizing agent for the conversion of alcohols to aldehydes and ketones110 and of indoles to 3-chloroindoles without formation of by-products111. N-[phenyliodine(III)] bisisatin can be obtained from the sodium salt of isatin and phenyliodine (IE) bistrifluoroacetate in 85% yield. This compound is a member of a group of iodine(III)imides,... 

The Step 5 product (0.06 mmol) dissolved in 3 ml CH2C12 was treated with triethy-lamine (0.07 mmol) and (S)-2-phenylethyloxy-carbonyloxysuccinimide (0.17 mmol), then stirred 18 hours. The solution was diluted with 15 ml CH2C12, washed with saturated NaHC03 solution, dried, and concentrated. The residue was purified by RP-HPLC and the product isolated in 28% yield as the bistrifluoroacetic acid salt. 

Diaryl sulfones. Arylthallium bistrifluoroacetates can be converted into diary) sulfones by reaction with an aqueous solution of sodium benzenesultinate and copper(II) sulfate (4 1) under mild conditions. The copper salt is essential. 

Aryl fluorides, 149 Arylpenta-2,4-dienoates, 161 a-Arylpropionic acids, 314 Arylsulfonylalkynes, 7 Arylthallium bistrifluoroacetates, 462 a-Atlantone, 514 Atiolactic acid methyl ether, 290 Aucubin, 73... 

A very large number of other arylthallium bistrifluoroacetates have been obtained by the direct thallation of aromatic compounds 40, 168,169,170, 203) (see Section VIII, B). 

Figure 4.2.2 Single Crystal X-Ray Diffraction Structure of the Bistrifluoroacetate Salt of [22]Porphyrin-(3.1.3.1) 4.70b.

Attempts at oxidizing the hexathia[36]hexaphyrin-(2.2.2.2.2.2) isomers 7.82a and 7.82b have been made." In the case of isomer 7.82a, treatment with bis(tri-fluoroacetoxy)iodobenzene in benzene and TFA was found to effect oxidation to the [34]hexaphyrin-(2.2.2.2.2.2) species 7.85 in 50% yield (Scheme 7.7.5). This macrocycle, isolated as its bistrifluoroacetate salt, was found to be aromatic, as judged from... 

TriaryWismuthine bistrifluoroacetates. These compounds are readily prepared from the corresponding diacetates on reaction with CF3COOH in dichloromethane at room temperature (3 examples, 75-87%). 

Phenyliodo(lll) bistrifluoroacetate, Nal, CH2CI2, 15 min. 84-92% yield. Iodine is generated in situ by this method. ... 

An intramolecular variation of the arylation reaction of a p-diketone led to cyclised products (24). The reaction involved the treatment of an a-(aryl)alkyl p-dicarbonyl derivative (22) with phenyl-iodine(in) bistrifluoroacetate (23), followed by base catalysed ligand coupling reaction. 2... 

Synthesis of compound (90) (case of p-naphthol) corresponding to the postulated intermediate in the 0-phenylation reaction was performed by the base-catalysed reaction of p-naphthol with triphenylbismuth bistrifluoroacetate. However, after decomposition, this reaction led only to the products of C-phenylation.24J0 (Scheme 6.12) Moreover, the C-phenylation is a fast reaction which can be completed at room temperature, or below, when the 0-phenylation under neutral or acidic conditions requires long periods of reflux of the benzene solutions. 

However, aryl cyanides are more directly obtained by reaction of the arylthallium compound with various copper cyanides. Different reaction systems have been reported, such as CuCN or Cu(CN)2 in acetonitrile or pyridine with arylthallium acetate perchlorate monohydrates. Other systems involve the arylthallium bistrifluoroacetate with CuCN in acetonitrileor in DMF. With these systems, a number of aryl cyanides (114), heteroaryl cyanides (115) 25,126 indolyl cyanides (116) and (117)124 148 have been prepared. 

Phenols arylboronic acids. Treatment of arylthallium bistrifluoroacetates with diborane in THF leads to an intermediate, possibly ArBHj, that is converted into arylboronic acids on treatment with water or into a phenol on treatment with alkaline hydrogen peroxide. Treatment of the intermediates with silver nitrate fails to produce biaryls. ... 

Arylthallium(III) bistrifluoroacetates (2). These substances can be prepared in high yield by replacement of a trimethylsilyl group (c/. 4, 282-283) ... 

The stereospecific oxidation of alkenes to give the bistrifluoroacetates of vic-diols (50—70 %) by the reagent (CFa COsIsI-n-CsHis at ca. 20 °C has been reported e.g. cyclohexene affords a mixture of cis- and frn s-l,2-bis(trifluoroacetoxy)cyclo-hexane in the ratio 94 6. Since the degree of specificity depends on the solvent employed, a concerted mechanism is ruled out and a two-step mechanism involving... 

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