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.
This Thermo Scientific Chemicals brand product was originally part of the Alfa Aesar product portfolio. Some documentation and label information may refer to the legacy brand. The original Alfa Aesar product / item code or SKU reference has not changed as a part of the brand transition to Thermo Scientific Chemicals.
Applications
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.
Solubility
Miscible with water, ethanol, benzene and acetonitrile.
Notes
Store in cool place. Moisture sensitive. It reacts with water and ethanol. Incompatible with water, acids and bases.
RUO – Research Use Only
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.