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Synlett 2006(7): 1130-1131  
DOI: 10.1055/s-2006-939723
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© Georg Thieme Verlag Stuttgart · New York

Diethylaminosulfur Trifluoride (DAST)

Sabrina Baptista Ferreira*
Centro de Tecnologia, Bloco A, Instituto de Química, Universidade Federal do Rio de Janeiro, 21941-590 Rio de Janeiro, Brazil
e-Mail: sabrinab@iq.ufrj.br;
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Publication History

Publication Date:
24 April 2006 (online)

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Introduction

Fluorination is an important structural modification for ­diverse classes of bioactive organic molecules. The introduction of a fluorine atom or fluorinated group into organic molecules often changes their physical, chemical and physiological properties, resulting in greater stability and lipophilicity of the molecule. [1] Diethylaminosulfur trifluoride (DAST) is a widely used fluorinating reagent, [2-6] which is very effective for converting alcohols, ketones, aldehydes and carboxylic acids into their corresponding fluoro derivatives. This reagent has its origins in the ­pioneering work of Middleton et al. at DuPont. [7] DAST is synthesized via the substitution of a fluorine atom of ­sulfur tetrafluoride (SF4) by a diethylamino group, resulting in a powerful fluorination agent (Scheme 1). DAST presents the following advantages: the product is rela­tively easy to handle and shows good selectivity, con­sequently being less prone to formation of olefins in elimination reactions and/or rearrangement reactions. This reagent is commercially available as liquid that can be handled at room temperature and in common laboratory glassware. However, DAST is unstable above 70 °C.

Scheme 1