Selective Nickel-Catalyzed Hydrodefluorination of Amides Using Sodium Borohydride

Abstract

Hydrodefluorination selective to the ortho position to amides is accomplished under mild conditions using sodium borohydride and a nickel catalyst. The facile formation of a nickelacycle intermediate with a specific geometry ensures selectivity without the need for electronic directing groups, and fluorine atoms in other positions remain intact. This method avoids the use of stoichiometric silanes which are typical for most other defluorination reactions, resulting in virtually no organic waste byproducts.

Nickel-catalysed chelation-assisted reductive defluorinative sulfenylation of trifluoropropionic acid derivatives

“…4 Directing group assisted C–F bond activation strategy can represent a pivotal approach for efficiently cleavage of unactivated C–F bond. 5 Notably, Chatani group reported a pioneering example using amide as a directing group for the nickel-catalysed cross-electrophile coupling via the activation of inert C(aryl)–F bond in the presence of Zn as a reductant (Scheme 1a). 6 Recently, Shi and coworkers developed a nickel-catalysed ester group promoted stereo- and enantioselective cross-coupling of gem -difluoroalkenes with benzyl chlorides using B 2 pin 2 as a stoichiometric reductant, involving C(alkene)–F bond activation (Scheme 1b).…”