Synlett 2013; 24(7): 891-892
DOI: 10.1055/s-0032-1318499
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© Georg Thieme Verlag Stuttgart · New York

Dialkylaminodifluorosulfinium Salts: XtalFluor-E and XtalFluor-M

Antonio Franconetti
Departamento de Química Orgánica, Facultad de Química, Universidad de Sevilla, Apartado de Correos No. 1203, 41071 Sevilla, Spain   Email: afranconetti@us.es
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Publication History

Publication Date:
19 March 2013 (online)

Introduction

Fluorination is an important reaction in medicinal chemistry.[1] Fluorinated analogues of biomolecules frequently show increased biological power, lipidic permeability and metabolic stability. Diethylaminosulfur trifluoride (DAST) has been widely used for directly replacing a hydroxyl group by fluorine under very mild conditions.[2] [3] Nevertheless, the corrosive properties of DAST make it unsuitable for high-scale usage.

In this context, commercially available aminodifluorosulfinium salts,[4] such as XtalFluor-E (1) or XtalFluor-M (2), are efficient alternatives. These fluorinating agents are crystalline, more selective and significantly more stable[5] than Deoxo-Fluor or DAST and do not react violently with water.[6]

Reaction of DAST with tetrafluroboric acid provides, by elimination of HF, diethylaminodifluorosulfinium tetrafluoroborate 1 in excellent yield (Scheme [1]).[5]

Zoom Image
Scheme 1