Quick and easy acyl fluorides | October 30, 2017 Issue - Vol. 95 Issue 43 | Chemical & Engineering News
Volume 95 Issue 43 | p. 7 | Concentrates
Issue Date: October 30, 2017

Quick and easy acyl fluorides

Bench-stable trifluoromethylthiolate salt simplifies functionalization of carboxylic acids
Department: Science & Technology
News Channels: Organic SCENE, Environmental SCENE
Keywords: Reagents, fluorination, trifluoromethylthiolate, acyl fluoride
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Tetramethylammonium trifluoromethylthiolate, [N(CH3)4]SCF3, is proving to be a versatile SCF3 transfer reagent and fluorinating reagent, as shown in this new reaction with carboxylic acids.
A reaction scheme shows conversion of generic carboxylic acids to acyl fluorides using an ammonium trifluoromethylthiolate salt.
 
Tetramethylammonium trifluoromethylthiolate, [N(CH3)4]SCF3, is proving to be a versatile SCF3 transfer reagent and fluorinating reagent, as shown in this new reaction with carboxylic acids.

Tetramethylammonium trifluoromethylthiolate, [N(CH3)4]SCF3, is a mouthful to say, but the inexpensive, bench-stable, and easy-to-use salt has been impressing chemists over the past few years for its versatility in adding SCF3 groups to molecules and as a fluorinating reagent. For example, Franziska Schoenebeck and her group at RWTH Aachen University have shown that [N(CH3)4]SCF3 has untapped potential as a fluorinated surrogate of thiophosgene (SCCl2), using it to functionalize alcohols and amines. Going further, Schoenebeck’s group has now used the trifluoromethylthiolate salt to convert aromatic and aliphatic carboxylic acids to acyl fluorides, which themselves are useful reagents (Org. Lett. 2017, DOI: 10.1021/acs.orglett.7b02516). The appeal of using [N(CH3)4]SCF3 to fluorinate carboxylic acids is its ability to replace specialized reagents derived from SF4. Those reagents often are toxic and corrosive, require additives, and tend to have poor functional-group tolerance and selectivity leading to undesired by-products. The trifluoromethylthiolate salt, first reported years ago but little used until recently, does away with those problems. Schoenebeck says her team has had “quite a lot of interest” from industry and other academic groups about using [N(CH3)4]SCF3, which could lead to efforts by her group to commercialize it.

 
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ISSN 0009-2347
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