II Trifluoroacetate

Preparative Methods obtained from dehydration of copper(II) trifluoroacetate hydrate.  

Cross-coupling. Copper(II) trifluoroacetate has been demonstrated to mediate the C-H bond arylation of arenes with arylboronic acids. Various arylboronic acids reacted with electron-rich benzene derivatives to give the corresponding biaryls in moderate to good yields (eq 1). In all cases, the cross-coupling product was solely obtained. 

Multiple C-H bond arylation is also possible. Copper(II) trifluoroacetate catalyzed the reaction of V-methylindole with phenyl boronic acid to afford the double arylated product in moderate yield (eq I)  

Oxyamination. Efficient oxyamination of styrene derivatives was described using copper(II) trifluoroacetate as the catalyst. The corresponding aminals were obtained in moderate to good yields (eq 3). The oxyamination was regioselective and was performed with various styrenes and electron-rich olefins. 

Arylation. Copper(II) trifluoroacetate was used to perform the arylation of indoles with triphenylbismuth bis-trifluoroacetate. Products bearing a C3 phenyl group were obtained with Cs-unsubstituted indoles (eq4) and IV-phenyl derivative with carbazole. 

---

Mercury(II) trifluoroacetate [13257-51-7] M 426.6. Recrystd from trifluoroacetic anhydride/trifluoroacetic acid [Lan and Kochi J Am Chem Soc 108 6720 7986]. Very TOXIC and hygroscopic. 

Palladium (II) trifluoroacetate [42I96-3I-6] M 332.4, m 210"(dec). Suspend in trifluoroacetic acid and evaporate on a steam bath a couple of times. The residue is then dried in vacuum (40-80°) to a brown powder. [J Chem Soc 3632 7965 J Am Chem Soc 102 3572 1980.]... 

Mercury(II) trifluoroacetate is a good electrophile that is highly reactive toward carbon-carbon double bonds [52, 53, 54] When reacting with olefins in nucleophilic solvents, it usually gives exclusively mercurated solvoadducts, but never products of skeletal rearrangement Solvomercuration-demercuratton of alkenes with mercury(II) trifluoroacetate is a remarkably effective procedure for the preparation of esters and alcohols with Markovnikov s regiochemistry [52, 5J] (equation 24)... 

A combination of xenon difluoride and CFjCOOH can trifluorometh-ylate appropriate substrates by free radicals arising out of the decomposition of xenon(II) trifluoroacetate (88JOC4582). 

It is believed that the regiospecifidty of the dioxabicyclization and the concurrent formation of bicyclic ethers 48 and 49 both result from equilibrium control of reversible (per)oxymercuration — de(per)oxymercuration. Thus to optimise the yield of 47 it is important to minimize the amount of water present in the reaction mixture and use of concentrated hydrogen peroxide (>80%) with anhydrous mercury(II) trifluoroacetate is recommended. 

An alternative entry into the [5.2.1] system was achieved by treating 2-cyclooctenyl hydroperoxide with mercury(II) trifluoroacetate then bromine (Eq. 41)s3). 

Copper(II) triflate has also been used for the carbenoid cyclopropanation reaction of simple olefins like cyclohexene, 2-methylpropene, cis- or rran.y-2-butene and norbomene with vinyldiazomethane 2 26,27). Although the yields were low (20-38 %), this catalyst is far superior to other copper salts and chelates except for copper(II) hexafluoroacetylaeetonate [Cu(hfacac)2], which exhibits similar efficiency. However, highly nucleophilic vinyl ethers, such as dihydropyran and dihydrofuran cannot be cyclopropanated as they rapidly polymerize on contact with Cu(OTf)2. With these substrates, copper(II) trifluoroacetate or copper(II) hexafluoroacetylaeetonate have to be used. The vinylcyclopropanation is stereospecific with cis- and rra s-2-butene. The 7-vinylbicyclo[4.1.0]heptanes formed from cyclohexene are obtained with the same exo/endo ratio in both the Cu(OTf)2 and Cu(hfacac)2 catalyzed reaction. The... 

However, cyclopropanation of cyclohexene with methyl (a-diazomethyl)acrylate 3 in the presence of copper(II) trifluoroacetate furnished the 7-exo-substituted bicyclo-[4.1.0]heptane preferentially28). 

M Fujino, O Nishimura. A new method for the cleavage of S-p-methoxy-benzyl and 5-t-butyl groups of cysteine residues with mercury(II) trifluoroacetate. J Chem Soc Chem Commun 998, 1976. 

The immobilized lactose (37 a) was employed in sulfatation reactions using SOs-NEts complex. After mercury(II) trifluoroacetate cleavage, a 2.7 1 mixture of 3 -sulfated lactose and lactose was isolated and separated using anionic exchange resin. 

There are very few known methods, for transesterifications using bulky alcohols. Thiol esters undergo ready mercury(II) trifluoroacetate-catalyzed transesterifications with tert-butyl alcohol. Potassium tert-butoxide in the... 

The selective oxidation of terminal aikenes to the corresponding methyl ketones was reported by Roussel and Mimoun in 1980 and can be carried out using f-butylperoxypalladium(II) trifluoroacetate (PPT) or alternatively catalytic amounts of... 

Trimethylsilyl-protected 1-isopropenylcyclobutanols were rearranged to cyclohexanones via a two-step reaction sequence.114 The vinylcyclobutanes 1 were first treated with mercury(II) trifluoroacetate. The crude products were then converted into chlorides (which can be isolated) and finally reduced with tributyltin hydride to give 2. Sometimes small amounts of five-mem-bered ring compounds, which are intermediates of this two-step ring enlargement, are formed as side products. 

That the mercurial species released during the ring-closure step can, at least with some mercury(ll) salts, recycle and act catalytically is shown by the finding that mercury (II) trifluoroacetate, used in 0.1 M proportions (and even lower), in aqueous acetone at room temperature catalyzes the reaction of alkene 43 (R1 = Me, R2 = R3 = Bn, R4 = Ac a-isomer), and gives the cyclized products in 96% yield as a mixture of the alcohol 46 (R2 = R3 = Bn, R4 = Ac) and its epimer at the alcohol center, in the ratio 8 1 [24]. 

Polystyrene-bound alkenes react with alcohols or amines in the presence of mercury(II) trifluoroacetate to yield 2-alkoxy- or 2-aminoethylmercury compounds [30]. The C-Hg bond can be reduced to a C-H bond by treatment with LiBH4, or converted into a C-I bond by treatment with iodine [30]. Organomercury compounds have been immobilized with polystyrene-bound carboxylates [31]. The resulting product was used as starting material for the preparation of radiolabelled 6-iodo DOPA (Figure 4.4). 

For cyclopropanation of very electron-rich alkenes such as vinyl ethers copper(II) trifluoroacetate, copper(II) hexafluoroacetylacetonate or rhodium(II) acetate are the catalysts of choice. Copper trifluoroacetate catalysed cyclopropanation of vinyldia-zomethane with dihydropyran gives the corresponding vinyl cyclopropane adduct in low yield (equation 17). In contrast, catalytic decomposition of phenyldiazomethane in the presence of various vinyl ethers results in high-yield phenylcyclopropane formation (equations 18 and 19)27. 

Carbenoid transformations involving competition between intramolecular cyclopropa-nation and /8-hydride elimination have been investigated149. The chemoselectivity of these catalytic transformations can be effectively controlled by the choice of catalyst. Rhodium(II) trifluoroacetate catalysed decomposition of diazoketone 111 proceeds cleanly to give only enone 112. However, rhodium(II) acetate or bis-(iV-t-butylsalicyladiminato) copper(II) cu(TBs)2 provides exclusively cyclopropanation product 113 (equation 102)149. 

Alkoxysulfenylation Dimethyl(methylthiosulfonium) tetra-fluoroborate, 121 Aminomercuration Mercury(II) trifluoroacetate, 175 Azaselenylation Benzeneselenenyl halides, 26 N-Phenylselenophthalimide, 245 Azasulfenylation... 

Dimethyl sulfoxide-Phosgene, 58 Palladium(II) trifluoroacetate, 236 Trimethylamine N-oxide, 325 Trimethylsilyl chlorochromate,... 

Phenyl ethylenesulfonate, 241 Tin(IV) chloride, 300 Containing one sulfur 2,4-Bis(4-me thoxyphenyl)-1,3-dithia-2,4-diphosphetane-2,4-disulfide, 38 Titanium(IV) chloride-Zinc, 310 Other five-membered heterocycles Carbon dioxide, 65 Methanesulfonyl chloride, 176 Six-membered rings Containing one nitrogen—piperidines Dichlorotris(triphenylphosphine)-ruthenium(II), 107 Mercury(II) trifluoroacetate, 175 Tetrakis(triphenylphosphine)-palladium(O), 289... 

Methoxy-2-methyl-3-trimethyl-silyloxy-1,3-pentadiene, 180 Organocopper reagents, 207 Organotin reagents, 211 Palladium(II) trifluoroacetate, 236 Tetrakis(triphenylphosphine)palla-dium(0), 289... 

Mercury(II) chloride, 175, 182 Mercury(II) trifluoroacetate, 175 Molybdenum Compounds Molybdenum carbonyl, 194 Molybdenum(VI) oxide, 279 Oxodiperoxymolybdenum(pyridine)-(hexamethylphosphoric triamide),... 

Palladium(II) trifluoroacetate, 236 Sodium borohydride-Tetrakis(tri-phenylphosphine)palladium(O), 168 Tetrakis(triphenylphosphine)palla-dium(0), 34, 103, 126, 142, 169, 202, 211, 220, 271, 289 Tetrakis(triphenylphosphine)palla-dium(0)-l, 2-Bis(diphenylphos-phine)ethane, 290 Tetrakis(triphenylphosphine)palla-dium(0)-Zinc, 346 Tributyltin hydride-Dichlorobis-(triphenylphosphine)palladium(II), 319... 

Metal-containing compounds, Rhodium Compounds (Continued) Hydridotetrakis(triphenylphosphine)-rhodium(I), 144 Rhodium(II) acetate, 226, 266 Rhodium(II) carboxylates, 226, 266 Rhodium(II) trifluoroacetate, 266 Tetra-jx3-carbonyldodecacarbonylhexa-rhodium, 152, 288... 

Acetoxylation of propene to allyl acetate can be performed in the liquid phase with high selectivity (98%) in acetic acid in the presence of catalytic amounts of palladium trifluoroacetate. The stability and activity of this catalyst can be considerably increased by adding copper (II) trifluoroacetate and sodium acetate as cocatalysts (100 °C, 15 bar, reaction time = 4 h, conversion = 70%, selectivity = 97%). Gas-phase procedures for the manufacture of allyl acetate are described in several patents and use conventional palladium catalysts deposited on alumina or silica, together with cocatalysts (Au, Fe, Bi, etc.) and sodium acetate. The activity and selectivity reported for these catalysts are very high (100-1000 g l-1 h-1, selectivity = 90-95% ).427 A similar procedure has been used for the synthesis of methallyl acetate from 2-methylpropene.428... 

---