Trifluoromethanesulfonyloxy

Anomalous Fischer cyclizations are observed with certain c-substituted aryl-hydrazones, especially 2-alkoxy derivatives[l]. The products which are formed can generally be accounted for by an intermediate which w ould be formed by (ip50-substitution during the sigmatropic rearrangement step. Nucleophiles from the reaction medium, e.g. Cl or the solvent, are introduced at the 5-and/or 6-position of the indole ring. Even carbon nucleophiles, e.g. ethyl acetoacelate, can be incorporated if added to the reaction solution[2]. The use of 2-tosyloxy or 2-trifluoromethanesulfonyloxy derivatives has been found to avoid this complication and has proved useful in the preparation of 7-oxygen-ated indoles[3]. 

D Boronic acid coupling 10 l-(4-Methylphenylsulfonyl)indole- l-Benzyl-3-trifluoromethanesulfonyloxy-l,2,5,6- 92 [10]... 

Trifluoromethanesulfonyloxy Methyl a-acetamidoacrylate, PdlOAclj, n-Bu N, LiCl, feis-(diphenylphosphinoferrocene) 38 [8]... 

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]... 

The influence of various buffers on the solvolysis of 5-(trifluoromethanesulfonyloxy)pent-2-yne in anhydrous 2,2,2-trifluoroethanol at 25 C for 24 hours has been studied.24 Sodium and calcium carbonate, 2,6-dimethylpyridine, pyridine and quinoline all favored the formation of four-membered rings, whereas potassium carbonate, triethylamine and sodium 2,2,2-trifluo-roethoxide suppressed formation of the rearranged products. One of the solvolysis products is 2,2,2-trifluoroethyl-2-methylcyclobutenyl ether (see Section 8.A.2.I.). 

In recent years, tnflate derivatives of trivalent iodine have found more and more applications as versatile reagents m organic synthesis [135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145] p-Oxo-bis[(trifluoromethanesulfonyloxy) (phenyl)iodine], which is readily available from lodosobenzene and tnflic anhydride (equation 44), is especially valuable for the preparation of alkynyl lodomum tnflates from silyl- or stannylacetylenes [136 (equation 70)... 

The introduction of acetylene, terminal alkynes or internal alkynes into methylene chloride solutions of iodosylbenzene and triflic acid [1 1, in situ generation of PhI(OH)OTf] results in the production of [j3-(trifluoromethanesulfonyloxy)vinyl]iodonium triflates (equation 172)78,133. Since the -configuration has been determined for selected members of this series (R1, R2 = n-Pr, H n-Bu, H), these reactions appear to proceed via stereoselective anti-additions of PhI(OH)OTf to the alkynes. 

To a solution of CuCI (10 mg, 0.1 mmol) and Pd(PPli3)4 (58 mg, 0.05 mmol) in DMF (25 ml) were added trimethyl(phenylethynyl)silane (0.98 ml, 6.0 mmol) and 4-(trifluoromethanesulfonyloxy)acetophenone (0.95 ml, 5.0 mmol) at r.t. The reaction mixture was stirred for 24 h at 80 °C, quenched with 3 M HCl and extracted with diethyl ether. The ethereal layer was washed with aqueous NaH-CO3 solution and then with brine and dried over MgS04. Filtration and evaporation provided a brown oil (GC yield 97%). Purification by column chromatography (Si02, hexane diethyl ether =1 1) followed by bulb-to-bulb distillation (200 to 210 °C/5 mmHg) gave 4-(phenylethynyl)acetophenone (0.98 g, 89% yield) as a colorless solid. 

The role of the silver salt is not completely understood. No evidence for a single electron transfer mechanism has been found. Although extremely reactive electrophilic fluorinating agents, such as xenon fluoride triflate (FXeOTf) or trifluoromethanesulfonyloxy fluoride (TfOF), may be generated from the combination of xenon difluoride and silver(I) triflate, the reaction appears to proceed following initial interaction of the alkcnc with the silver ion.5... 

B. (R)-(+)-2 Diphenylphosphinyl-2 -trifluoromethanesulfonyloxy-1,1 -binaphthyt (3). A dry, 500-mL, Schienk tube is fitted with a magnetic stirring bar and a rubbei septum, and flushed with nitrogen gas. The flask is charged with 25.0 g (45.4 mmol) o... 

Maes and co-workers synthesized 5-chloro-2-methyl-4-trifluoromethanesulfony-loxypyridazin-3(2//)-one (28) and its 4-chloro-5-trifluoromethanesulfonyloxy-(30) regioisomer from the corresponding chloro-hydroxypyridazin-3(2//)-ones (27, 29) by esterification with triflic anhydride using triethylamine as base [30]. The trifluoromethanesulfonyloxypyridazin-3(2//)-ones (28, 30) are usually purified by one or more simple extractions (wash steps) followed by drying over MgSO4. 

The usefulness of the PMF strategy has also been demonstrated in the construction of several new polycyclic skeletons that contain a pyridazin-3(2FZ)-one moiety. The dibenzo[f,/z]phthalazin-l(2FZ)-one skeleton was synthesized via Suzuki cross-coupling of 2-benzyl-5-trifluoromethanesulfonyloxy-4-phenylpyridazin-3(2//)-one (132) with... 

Catalytic asymmetric synthesis of the key intermediate 11 in the preparation of 3/1.8/ , 10a-trihydroxycapnellene and 3/ ,8/J,10a,14-telrahydroxycapnellene is achieved upon treatment of 5-methyl-5-(3-trifluoromethanesulfonyloxy-3-butenyl)-1.3-cyclopentadiene (10) with catalytic amounts of palladium(II) acetate, (S)-BINAP and tetrabutylammonium acetate in dimethyl sulfoxide. The (.STS..S (-enantiomer of 11 is obtained in 89% yield and 80% ce23,8 . In a similar cyclization reaction of the substrate which contains a vinyl iodide unit in the side chain, a much lower asymmetric induction w7as observed. 

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