Difluoro compound diethylaminosulfur trifluoride

However, when ethyl acetoacetate was treated with diethylaminosulfur trifluoride, an entirely unexpected difluoro compound, C6H8F202, was obtained. The compound was an ester, and decolorized a solution of bromine in carbon tetrachloride. What is the structure of the product ... 

Similar reactions of diethylaminosulfur trifluoride take place with 2,4-pentanedione (acetylacetone), with butyl acetoacetate, and with ethyl 3-oxooctanoate, giving the corresponding difluoro compounds as E/Z mixtures in the ratio of 1 1 [9]. 

Table 2. gew-Difluoro Compounds from Aldehydes or Ketones and Diethylaminosulfur Trifluoride... 

Protein-tyrosine (PTP) inhibitors are potentially valuable pharmacological tools for studying cellular signal transduction and for therapeutic intervention. Derivatives of 1,1-difluoromethylphosphonic acid are known to be potent PTP inhibitors. An important method for synthesis of these compounds is fluorina-tion of acyl phosphonates by diethylaminosulfur trifluoride (DAST). This method allows synthesis of fcrf-butyl-protected difluoro(aryl)- or (naphthal-enyl)methylphosphonates, which under mildly acidic deprotection conditions afford desirable phosphonic acids [16, 39]. Acyl phosphonate fluorination by DAST has also been utilized for synthesis of a,a-(difluoroprop-2-ynyl)phos-phonates [14]. 

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