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Diethylaminosulfur trifluoride (DAST) is the organosulfur compound with the formula Et 2 NSF 3. This liquid is a fluorinating reagent used for the synthesis of organofluorine compounds . [ 1 ] The compound is colourless; older samples assume an orange colour.
The mechanism of fluorination by DAST parallels that of sulfur tetrafluoride. Attack of the hydroxyl group of the substrate on sulfur and elimination of hydrogen fluoride lead to an alkoxyaminosulfur difluoride intermediate. Nucleophilic attack by fluoride, either by an S N 1 [5] or S N 2 [6] pathway, leads to the product. Although clean ...
DAST may refer to: Diethylaminosulfur trifluoride, an organosulfur compound; Draw-a-Scientist Test, designed to investigate children's perceptions of the scientist;
Apart from DAST, a wide variety of similar reagents exist, including, but not limited to, 2-pyridinesulfonyl fluoride (PyFluor) and N-tosyl-4-chlorobenzenesulfonimidoyl fluoride (SulfoxFluor). [21] Many of these display improved properties such as better safety profile, higher thermodynamic stability, ease of handling, high enantioselectivity ...
This was demonstrated in the synthesis of meso-difluorosuccinate from (L)-tartrate and the synthesis of (D)- and (L)-difluorosuccinate from meso-tartrate. [6] Carbonyl compounds generally react with SF 4 to yield geminal difluorides. Reaction times tend to be on the order of hours and yields are moderate. [7]
4,4′-Diamino-2,2′-stilbenedisulfonic acid is the organic compound with the formula (H 2 NC 6 H 3 SO 3 H) 2 C 2 H 2.It is a white, water-soluble solid. Structurally, it is a derivative of trans-stilbene, containing amino and sulfonic acid functional groups on each of the two phenyl rings.
Electrophilic fluorinating reagents could in principle operate by electron transfer pathways or an S N 2 attack at fluorine. This distinction has not been decided. [2] By using a charge-spin separated probe, [3] it was possible to show that the electrophilic fluorination of stilbenes with Selectfluor proceeds through an SET/fluorine atom transfer mechanism.
In organic synthesis, SF 4 is used to convert COH and C=O groups into CF and CF 2 groups, respectively. [10] The efficiency of these conversions are highly variable. In the laboratory, the use of SF 4 has been superseded by the safer and more easily handled diethylaminosulfur trifluoride, (C 2 H 5) 2 NSF 3, "DAST": [11] This reagent is prepared ...