Bis(2-methoxyethyl)aminosulfur Trifluoride: A New Broad-Spectrum Deoxofluorinating Agent with Enhanced Thermal Stability
Gauri S. Lal,* Guido P. Pez, Reno J. Pesaresi, Frank M. Prozonic and Hansong Cheng
*Air Products and Chemicals Inc., 7201 Hamilton Boulevard, Allentown,
Pennsylvania 18195-1501, Email: lalgsapci.com
G. S. Lal, G. P. Pez, R. J. Pesaresi, F. M. Prozonic, H. Cheng, J. Org. Chem., 1999, 7048-7054.
DOI: 10.1021/jo990566+
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Abstract
Bis(2-methoxyethyl)aminosulfur trifluoride (Deoxo-Fluor reagent) is a new deoxofluorinating agent that is much more thermally stable than DAST (C2H5)2NSF3. It is effective for the conversion of alcohols to alkyl fluorides, aldehydes and ketones to the corresponding gem-difluorides, and carboxylic acids to the trifluoromethyl derivatives with, in some cases, superior performance compared to DAST.
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Details
Bis(2-methoxyethyl)aminosulfur trifluoride, also known as the Deoxo-Fluor reagent, is a new deoxofluorinating agent developed by Gauri S. Lal and colleagues at Air Products and Chemicals Inc. It offers significantly enhanced thermal stability compared to DAST (diethylaminosulfur trifluoride), making it safer for large-scale and high-temperature applications. The Deoxo-Fluor reagent effectively converts alcohols to alkyl fluorides, aldehydes/ketones to gem-difluorides, and carboxylic acids to trifluoromethyl derivatives, often with superior performance to DAST. This increased stability is due to the conformational rigidity provided by the coordination of alkoxy groups with the electron-deficient sulfur atom.
Thermal analysis shows that Deoxo-Fluor decomposes more slowly and with less heat and gas evolution than DAST. The reagent's broad applicability and improved selectivity in fluorination reactions make it a valuable tool in the synthesis of organofluorine compounds, which are important in medicinal and agrochemical industries. The synthesis of Deoxo-Fluor involves reacting the N-trimethylsilyl derivative of bis(2-methoxyethyl)amine with SF4. The reagent is commercially available and has been shown to be effective in various fluorination reactions, including those involving alcohols, aldehydes, ketones, carboxylic acids, sulfides, sulfoxides, and thioesters.
G. S. Lal, E. Lobach, A. Evans, J. Org. Chem., 2000, 65, 4830-4832.
Key Words
Fluoroalkanes, Benzyl Fluorides, Difluoroalkanes, Acyl Fluorides
ID: J42-Y1999-490