Diethylaminosulfur trifluoride

Caution This procedure should be conducted in a good hood to avoid exposure to sulfur teirajluoride. Protective gloves should be worn when handling diethylaminosulfur trifluoride since this material can cause severe HF burns. 

This preparation of diethylaminosulfur trifluoride is an adaptation of a procedure first described by von Halasz and Glemser. The same procedure can also be used to prepare other dialkylaminosulfur trifluorides by the substitution of the diethylaminotrimethylsilane with other dialkylaminotrimethylsilanes. ... 

Diethylaminosulfur trifluoride (DAST) reacts with epoxides to give com plex mixtures in which vicinal as difluorides, gemmal difluorides, and bis(2-fluoroalkyl) ethers are the mam components I6 (equations 16 and 17)... 

Table 6b. Fluorination of Secondary Alcohols with Diethylaminosulfur Trifluoride (DAST)...

The transformation of an ester carbonyl group to a difluoromethylene group, which IS usually difficult to perform, can be accomplished by conversion to the thiaesier followed by treatment with diethylaminosulfur trifluoride (DAST). A vanety of ester types react efficiently, although the reaction fails with lactones. Remarkably, trimethylsilylmethyl esters carry through the proeedure with the silyl group intact [13] (equation 17). 

In addition to the perfluoroalkylzinc compounds, the zinc reagent formed from 1,1,1-trifluorotrichloroethane has received considerable attention. This zinc compound was first reported as a stable ether complex [56]. Later, the DMF complex was isolated and the structure was determined by X-ray diffraction and shown to be monomeric [57] (equation 50). This zinc reagent undergoes a variety of functionalization reactions, and some typical examples are illustrated in Table 2 [47, 58, 59, 60, 61] The alcohol products (Table 2) can be converted to AiCF=CXCF3 (X = Cl, F) by further reaction with diethylaminosulfur trifluoride (DAST) and l,8-diazabicyclo[5 4.0]undec-7-ene (DBU) [60]... 

Dialkylaminosulfur trifluorides, - exemplified by diethylaminosulfur trifluoride (Et2NSF3, DAST), were introduced into carbohydrate chemistry as fluorinating agents by Sharma and Korytnyk, and they can be... 

A-Acetyl-9-deoxy-9-fluoroneuraminic acid (591) was prepared by treatment of a protected 6-hydroxyl precursor with A, A-diethylaminosulfur trifluoride (DAST) or through condensation of 2-acetamido-2,6-dideoxy-6-fluoro-D-mannopyranose with potassium di(/ >r/-butyl) oxaloacetate. Compound 591 is a substrate for cytidine monophosphate (CMP)-sialic acid synthetase, giving rise to CMP-5-A-acetyl-9-deoxy-9-fluoroneuraminic acid, which is cytotoxic against tumor cells. 5-A-Acetyl-3-fluoroneuraminic acids 592-594 were prepared through fluorine (or acetyl hypofluorite) addition (in AcOH) to methyl 5-acetamido-4,7,8,9-tetra-0-acetyI-2,6-anhy-dro-2,3,5-trideoxy-D- /ycm>D- a/arto-non-2-enopyranosate. Compound 592 was found to be a potent neuraminidase inhibitor. 

Displacement of the 3-hydroxyl group of 74 was carried out with Et2NSF3 (DAST) (DAST - diethylaminosulfur trifluoride) in dichloromethane. The expected fluorinated product 75 on treatment with aqueous perchloric acid led to regioselective epoxide ring opening to give 76, which on treatment with hydrazine hydrate at 100 °C for 18 h yielded 3,4-dihydroxy-8-oxo-octahydropyridazino[l,6-r/][l,2,4]triazine-l-carboxylic acid phenylamide 77 (Scheme 3) <1997T9357>. 

Despite the high utility of glycosyl fluorides as stand-alone glycosyl donors, there has been only one example of a direct dehydrative glycosylation whereby hemiacetal activation proceeds through a glycosyl fluoride intermediate. Hirooka and Koto have detailed the use of diethylaminosulfur trifluoride (DAST) for dehydrative glycosylations with hemiacetal donors (Scheme 3.16) [160]. Treatment of a mixture of hemiacetal 1 and alcohol acceptor (R OH) with DAST 108 (2 equiv) at 0°C provides the... 

Treatment of thioglycosides with /V-bromosuccinimide (NBS) in the presence of diethylaminosulfur trifluoride (DAST) or HF-pyridine complex furnishes glycosyl fluorides.23 These can be activated with AgC104/SnCL in the presence of another... 

FIGURE 7.19 Reagents for preparing A-protected amino-acid fluorides,55-5661 Boc2-amino-acid fluorides (CyNF),58-59 and a nonbasic acid scavenger (BSA).62 CyNF = cyanuric fluoride DAST = diethylaminosulfur trifluoride TFFH = tetramethylfluoroformamidinium hexafluo-rophosphate BSA = b (trimethylsilyl)acetimide. 

Diethylaminosulfur trifluoride, 1684 Diphosphoryl chloride, 4168 Diselenium dichloride, 4115 Disulfur dibromide, 0282 Disulfur dichloride, 4114 Disulfuryl dichloride, 4103... 

REACTION OF SULFOXIDES WITH DIETHYLAMINOSULFUR TRIFLUORIDE PREPARATION OF FLUOROMETHYL PHENYL SULFONE, A REAGENT FOR THE SYNTHESIS OF FLUOROALKENES (Benzene, [(fluoromethyl)sulfonyl]-)... 

Diethylaminosulfur trifluoride (DAST) should be handled using appropriate safety equipment (rubber gloves and goggles). DAST was purchased from Carbolabs, Inc., and used as received. 

Diethylaminosulfur trifluoride Sulfur, (diethylaminato)trifluoro- (9) (38078-09-0) Fluoromethyl phenyl sulfide Benzene, [(fluoromethyl)thio]- (9) (60839-94-3)... 

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