Trifluoroacetic Anhydride-Sodium Iodide

Drabowicz, J. and Oae, S. (1977) Mild reductions of sulfoxides with trifluoroacetic anhydride/ sodium iodide system. Synthesis, 404-405. 

Triethylsilyl-l,3-butadiene, 502 Triflic acid, 504 Trifluoroacetic acid, 1, 503 Trifluoroacetic anhydride-Pyridine, 504 Trifluoroacetic anhydride-Sodium iodide,... 

Quinoxaline 1,4-dioxide derivatives were reduced by hexachlorodisilane to give the corresponding quinoxalines (eq 5). Also evaluated in the study were the reducing agents iodotri-methylsilane, trifluoroacetic anhydride-sodium iodide, and titanium(IV) chloride-zinc dust. Hexachlorodisilane, for its convenience and efficiency, was recommended by the authors as the reagent of choice for this transformation. 

Sulfoxides are reduced to sulfides under mild conditions with Trifluoroacetic Anhydride-Sodium Iodide (eq 6). ... 

Sodium iodide in trifluoroacetic anhydride reacts with epoxides to form the corresponding alkenes in high yields [39] The reduction is stereospecific and generates olefins of the same geometry as the starting epoxides [39]... 

Using Sodium Iodide with Trifluoroacetic Anhydride or Sulfur Trioxide-Pyridine... 

Marchand and co-workers reported a synthetic route to TNAZ (18) involving a novel electrophilic addition of NO+ NO2 across the highly strained C(3)-N bond of 3-(bromomethyl)-l-azabicyclo[1.1.0]butane (21), the latter prepared as a nonisolatable intermediate from the reaction of the bromide salt of tris(bromomethyl)methylamine (20) with aqueous sodium hydroxide under reduced pressure. The product of this reaction, A-nitroso-3-bromomethyl-3-nitroazetidine (22), is formed in 10% yield but is also accompanied by A-nitroso-3-bromomethyl-3-hydroxyazetidine as a by-product. Isolation of (22) from this mixture, followed by treatment with a solution of nitric acid in trifluoroacetic anhydride, leads to nitrolysis of the ferf-butyl group and yields (23). Treatment of (23) with sodium bicarbonate and sodium iodide in DMSO leads to hydrolysis of the bromomethyl group and the formation of (24). The synthesis of TNAZ (18) is completed by deformylation of (24), followed by oxidative nitration, both processes achieved in one pot with an alkaline solution of sodium nitrite, potassium ferricyanide and sodium persulfate. This route to TNAZ gives a low overall yield and is not suitable for large scale manufacture. 

Chemical deoxygenation of sulfoxides to sulfides was carried out by refluxing in aqueous-alcoholic solutions with stannous chloride (yields 62-93%) [186 Procedure 36, p. 214), with titanium trichloride (yields 68-91%) [203], by treatment at room temperature with molybdenum trichloride (prepared by reduction of molybdenyl chloride M0OCI3 with zinc dust in tetrahydrofuran) (yields 78-91%) [216], by heating with vanadium dichloride in aqueous tetrahydrofuran at 100° (yields 74-88%) [216], and by refluxing in aqueous methanol with chromium dichloride (yield 24%) [190], A very impressive method is the conversion of dialkyl and diaryl sulfoxides to sulfides by treatment in acetone solutions for a few minutes with 2.4 equivalents of sodium iodide and 1.2-2.6 equivalents of trifluoroacetic anhydride (isolated yields 90-98%) [655]. 

Miki and Hachiken reported a total synthesis of murrayaquinone A (107) using 4-benzyl-l-ferf-butyldimethylsiloxy-4fT-furo[3,4-f>]indole (854) as an indolo-2,3-quinodimethane equivalent for the Diels-Alder reaction with methyl acrylate (624). 4-Benzyl-3,4-dihydro-lfT-furo[3,4-f>]indol-l-one (853), the precursor for the 4H-furo[3,4-f>]indole (854), was prepared in five steps and 30% overall yield starting from dimethyl indole-2,3-dicarboxylate (851). Alkaline hydrolysis of 851 followed by N-benzylation of the dicarboxylic acid with benzyl bromide and sodium hydride in DMF, and treatment of the corresponding l-benzylindole-2,3-dicarboxylic acid with trifluoroacetic anhydride (TFAA) gave the anhydride 852. Reduction of 852 with sodium borohydride, followed by lactonization of the intermediate 2-hydroxy-methylindole-3-carboxylic acid with l-methyl-2-chloropyridinium iodide, led to the lactone 853. The lactone 853 was transformed to 4-benzyl-l-ferf-butyldimethylsiloxy-4H-furo[3,4- 7]indole 854 by a base-induced silylation. Without isolation, the... 

TNB, Methanol, Potassium iodide, Hydrochloric acid, Sodium bisulfite, Methylene chloride, Magnesium sulfate Hydroxylamine hydrochloride, Glyoxal, Sodium carbonate, Ethanol, Chlorine, Chloroform, Methanol, Ethylenediamine, Ethylene glycol, Sodium hydroxide, Trifluoroacetic anhydride, Nitric acid, Acetone... 

Sodium iodide in trifluoroacetic anhydride reacts with epoxides to form the ... 

Trifluoroacetyl iodide, generated in situ from trifluoroacetic anhydride and sodium iodide, deoxygenates epoxides.The reaction begins by anti opening of the epoxide, followed by the formation of an... 

Bis-deoxygenation of 2,3-disubstituted quinoxaline di-A -oxides has been performed under very mild conditions with a variety of reagents, such as hex-achlorodisilane or trifluoroacetic anhydride plus sodium iodide. ... 

Deoxygenation of epoxides. Epoxides react with trifluoroacetic anhydride (1 equiv.) and sodium iodide (1 equiv.) in CH3CN-THF (1 1) to give a jS-iodotri-fluoroacetate when this product is treated with sodium iodide (3 equiv.) in the same solvent system, an olefin, sodium trifluoroacetate, and iodine are formed. The olefin has the same geometry as the starting epoxide yields of the olefin are 80-95%. Presumably, trifluoroacetyl iodide is generated in situ from the anhydride and Nal. ... 

Several new methods for the reduction of sulphoxides to sulphides have appeared. Trifluoroacetic anhydride has been used in conjunction with dimethyl sulphide, hydrogen sulphide, " or sodium iodide. The silicon compounds bromo- and iodo-trimethylsilane, or the phenyltrimethylsilane-iodine combina-... 

Additive Pummerer reactions of the type described above using racemic a,P-unsaturated sulfoxides can be accomplished using the following electrophiles acyl chlorides [205,206], dithioacetic acid [207], acetic anhydride [208], mineral acids/alcohols [209], phosphorus pentachloride [210], silyl ketene acetals/zinc iodide [211], thionyl chloride [212], oxalyl chloride [213], trifluoroacetic acid and its anhydride [214-218], triflic anhydride/sodium acetate [219], and dichloroketene (see below). Selected recent examples of work in this area are presented here. 

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