Triflates compounds

Aryl fluorosulfonates have recently been reported as less expensive alternatives to aryl triflates. Compound 3 has been synthesized in 50% isolated yield using 4-nitrophenyl fluorosulfonate as the electrophilic partner in the cross-coupling reaction. Roth, G. P. Fuller, C. E. J. Org. Cham. 1991,56,3493-3496. 

Selective reaction of the bromochloro compound 83 with silver fluoride in acetonitrile gave a good yield of the product of nucleophilic displacement of bromide with inversion of configuration, namely, 151, and treatment with an excess of the reagent afforded25 the g m-difluoride (152). With alcohols in the presence of silver triflate, compound 83 affords access to orthoesters (for example, the dimethyl compound 153), and with diols sp/ro-analogs (for example, 154, which has the orthoester structural feature of the orthosomy-cins), are obtained.88... 

All cyclopentasilanes investigated so far have been prepared from deca-phenylcyclopentasilane by deaiylation with triflic acid (triflation) and subsequent reaction of the triflate compounds with lithium halides, potassiiun halides or lithium aluminum hydride. The reaction sequences are symbolized below (Scheme 1, phenyl groups are not shown). 

Complexation of silver(I) triflate and tosylate salts to the related A, 7V -bis(hexadecanoyl)-l,10-diaza-4,7,13,16-tetrathiacyclooctadecane also formed smectic A phase, between 74 °C and 107 °C for the triflate compound, and between 125 °C and 173 °C for the tosylate. ... 

The endIcT-selective hetero Dids-Alder reaction of chiral oxazolidones 12 with (Z)-l-acetoxy-2-ethoxyethene yields the 1-substituted glycals 13 as the major products when catalysed with dimethylaluminium chloride, and 14 as the major products when catalysed with trimeth silyl triflate. Compounds 13 (R = Et)and 14 (R = Et) were subsequently converted into ethyl P-D-mannopyranoside and ethyl 3-L-mannopyrannoside, respectively. ... 

On the basis of the studies described in the preceding chapters, we anticipated that chelation is a requirement for efficient Lewis-acid catalysis. This notion was confirmed by an investigation of the coordination behaviour of dienophiles 4.11 and 4.12 (Scheme 4.4). In contrast to 4.10, these compounds failed to reveal a significant shift in the UV absorption band maxima in the presence of concentrations up to one molar of copper(ir)nitrate in water. Also the rate of the reaction of these dienophiles with cyclopentadiene was not significantly increased upon addition of copper(II)nitrate or y tterbium(III)triflate. 

The most useful pseudo-halides are aryl triflates (trifluoromethylsulfonates) of phenols and enol triflates derived from carbonyl compounds[4,5,6]. 

Diene carboxylates can be prepared by the reaction of alkenyl halides with acrylates[34]. For example, pellitorine (30) is prepared by the reaction of I-heptenyl iodide (29) with an acrylate[35]. Enol triflates are reactive pseudo-halides derived from carbonyl compounds, and are utilized extensively for novel transformations. The 3,5-dien-3-ol triflate 31 derived from a 4,5-unsaturated 3-keto steroid is converted into the triene 32 by the reaction of methyl acrylate[36]. 

The metallic salts of trifluoromethanesulfonic acid can be prepared by reaction of the acid with the corresponding hydroxide or carbonate or by reaction of sulfonyl fluoride with the corresponding hydroxide. The salts are hydroscopic but can be dehydrated at 100°C under vacuum. The sodium salt has a melting point of 248°C and decomposes at 425°C. The lithium salt of trifluoromethanesulfonic acid [33454-82-9] CF SO Li, commonly called lithium triflate, is used as a battery electrolyte in primary lithium batteries because solutions of it exhibit high electrical conductivity, and because of the compound s low toxicity and excellent chemical stabiUty. It melts at 423°C and decomposes at 430°C. It is quite soluble in polar organic solvents and water. Table 2 shows the electrical conductivities of lithium triflate in comparison with other lithium electrolytes which are much more toxic (24). 

The fluoraza reagents consist of two types of compounds one in which a fluorine atom is bound to the nitrogen atom of an amide or, more often, a sulfonamide and one in which a fluorine atom is bound to the nitrogen atom of a tertiary amine such as pyridine, quinuclidine, or triethylenediamine 1,4-diaza-bicyclo[2 2.2]octane. The positive charge on the nitrogen is counterbalanced by a non-nucleophilic anion such as triflate or tetrafluoroborate. 

An interesting class ot covalent Inflates are vin l and ar>/ or heteroaryl Inflates Vinyl inflates are used for the direct solvolytic generation of vinyl cations and for the generation of unsaturated carbenes via the a-elimination process [66] A triflate ester of 2-hydroxypyridine can be used as a catalyst for the acylation of aromatic compounds with carboxylic acids [109] (equation 55)... 

Triflates of aluminum, gallium and boron, which are readily available by the reaction of the corresponding chlorides with triflic acid, are effective Fnedel-Crafis catalysis for alkylation and acylation of aromatic compounds [119, 120] Thus alkylation of toluene with various alkyl halides m the presence of these catalysts proceeds rapidly at room temperature 111 methylene chloride or ni-tromethane Favorable properties of the triflates in comparison with the correspond mg fluorides or chlorides are considerably decreased volatility and higher catalytic activity [120]... 

Triflates of titanium and tin are effective catalysts for various condensations of carbonyl compounds [I2I, 122, 123, 124, 125] Claisen and Dieckmann type condensations between ester functions proceed under mild conditions in the presence of dichlorobis(trifluoromethanesulfonyloxy)titaiiiuin(rV) and a tertiary amine (equations 59 and 60) These highly regio- and stereoselective condensations were used successfully m the synthesis of carbohydrates [122]... 

Silver(I) triflate is widely applied to the preparation of various derivatives of triflic acid, both covalent esters [66] and ionic salts For example, it can be used for the in situ generation of iodine([) triflate, a very effective lodinatmg reagent for aromatic and heteroaromatic compounds [130] (equations 65 and 66)... 

Compound 40 has not yet been synthesized. However, there is a large body of synthetic data for nucleophilic substitution reactions with derivatives of 41 [synthesized from aliphatic and aromatic aldehydes, pyridine, and trimethylsilyl triflate (92S577)]. All of these experimental results reveal that the exclusive preference of pathway b is the most important feature of 41 (and also presumably of 40). 

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