Cookies disclaimer

I agree Our site saves small pieces of text information (cookies) on your device in order to deliver better content and for statistical purposes. You can disable the usage of cookies by changing the settings of your browser. By browsing our website without changing the browser settings you grant us permission to store that information on your device.

38078-09-0 - Diethylaminosulfur trifluoride, 95% - DAST - A11992 - Alfa Aesar

A11992 Diethylaminosulfur trifluoride, 95%

CAS Number

Size Price ($) Quantity Availability
5g 80.70
25g 259.00
100g 633.00
Add to Cart Add to Quote Request View Item

Diethylaminosulfur trifluoride, 95%


Chemical Properties

Formula Weight
Boiling Point
Flash Point
Refractive Index
Moisture Sensitive
Miscible with water, ethanol, benzene and acetonitrile.


Diethylaminosulfur trifluoride (DAST) is used as a precursor to prepare 2,6-dimethoxybenzoyl fluoride and 2-thiazolines. It is a useful fluorinating agent used for a variety of compounds including alcohols, thioethers, alkenols and cyanohydrins. It also serves as a catalyst for Friedel-Crafts allylation reaction using tertiary cyclopropyl silyl ethers and in the rearrangement of homoallylic alcohols to unsaturated aldehydes. It plays an important role for gem difluorination of ketopipecolinic acids.


Store in cool place. Moisture sensitive. It reacts with water and ethanol. Incompatible with water, acids and bases.

Literature References

Reagent for conversion of alcohols to alkyl fluorides and carbonyl compounds to gem-difluorides, less prone to cause dehydration or rearrangement than SF4: J. Org. Chem., 40, 574 (1975); Org. Synth. Coll., 6, 835 (1988); Eur. J. Org. Chem., 3177 (2000); Tetrahedron Lett, 44, 6661 (2003); reviews: Org. React., 35, 513 (1988); Austral. J. Chem., 54, 75 (2001); Synlett, 1130 (2006). Conversion of alcohols to fluorides has been accomplished with stereocontrol at the chiral center: Tetrahedron: Asym., 4, 161 (1993).

Use of dichloromethane as solvent permits the selective monofluorination of sugars: J. Org. Chem., 48, 393 (1983). Glycosyl fluorides, which are useful building blocks for oligosaccharides: J. Am. Chem. Soc., 105, 2430 (1983), and C-glycosides, can be prepared by reaction of DAST with phenylthioglycosides: J. Am. Chem. Soc., 106, 4189 (1984). The reaction with diols can lead to difluorides, sulfite esters or cyclic ethers: J. Chem. Soc., Perkin 2, 861 (1995).

Convenient reagent for conversion, in the absence of base, of N-protected amino acids to the acyl fluorides: Lett. Pept. Sci., 2, 285 (1996); Indian J. Chem., 39, 384 (2000); compare Cyanuric fluoride, A15666. Review of peptide coupling via amino acid halides: Acc. Chem. Res., 29, 268 (1996). See also Appendix 6.

In the presence of SbCl3, promotes the fluoro-Pummerer rearrangement of sulfoxides: J. Am. Chem. Soc., 107, 735 (1985); Org. Synth. Coll., 9, 446 (1998):

Direct conversion of thioethers to the ɑ-fluoro analogues has also been reported: J. Org. Chem., 58, 3800 (1993). Fluorination of thioesters leads to ɑɑ-difluoroethers: J. Org. Chem., 55, 768 (1990):

See also 4-Morpholinyl­sulfur trifluoride, L19751.

Gao, X.; Tang, X. Effective reduction of graphene oxide thin films by a fluorinating agent: Diethylaminosulfur trifluoride. Carbon 2014, 76, 133-140.

Anxionnat, B.; Robert, B.; George, P.; Ricci, G.; Perrin, M. A.; Pardo, D. G.; Cossy, J. Correction to Ring Expansion of Cyclic beta-Amino Alcohols Induced by Diethylaminosulfur Trifluoride: Synthesis of Cyclic Amines with a Tertiary Fluoride at C3. J. Org. Chem. 2014, 77 (14), 6087-6099.

GHS Hazard and Precautionary Statements

Hazard Statements: H226-H331-H314-H318

Flammable liquid and vapour. Toxic if inhaled. Causes severe skin burns and eye damage. Causes serious eye damage.

Precautionary Statements: P260-P201-P280-P304+P340-P405-P501a

Do not breathe dust/fume/gas/mist/vapours/spray. Obtain special instructions before use. Wear protective gloves/protective clothing/eye protection/face protection. IF INHALED: Remove to fresh air and keep at rest in a position comfortable for breathing. Store locked up. Dispose of contents/container in accordance with local/regional/national/international regulations.

Other References

Hazard Class
Packing Group
Harmonized Tariff Code


Recently Viewed


Life Science

Metals & Materials


Analytical & Labware