An N-Fluorinated Imide for Practical Catalytic Imidations

Abstract

Catalytic imidation using NFSI as the nitrogen source has become an emerging tool for oxidative carbon–nitrogen bond formation. However, the less than ideal benzenesulfonimide moiety is incorporated into products, severely detracting its synthetic value. As a solution to this challenge, we report herein the development of a novel N-fluorinated imide, N-fluoro-N-(fluorosulfonyl)­carbamate (NFC), by which the attached imide moiety acts as a modular synthetic handle for one-step derivatization to amines, sulfonamides, and sulfamides. Furthermore, this study revealed the superior reactivity of NFC as showcased in a copper-catalyzed imidation of benzene derivatives and imidocyanation of aliphatic alkenes, overcoming the limitation of NFSI-mediated reactions.

N-Fluorobenzenesulfonimide (NFSI) analogs with deprotectable substituents: synthesis of β-fluoroamines via catalytic aminofluorination of styrenes

“…In particular, our group is developing practical N–F reagents bearing easily deprotectable substituents on the nitrogen atom to replace NFSI. 10 Recently, Aikawa and Hashimoto et al reported a novel N–F reagent, N -fluoro- N -(fluorosulfonyl)carbamate (NFC). 10 b With this N–F reagent, the elimination of fluorine allowed the transformation of arenes and alkenes to amines whose nitrogen atoms were protected by the sulfonyl and alkoxycarbonyl moieties.…”

“…The novel N–F reagents bearing Ns group(s) were synthesized as summarized in Scheme 2. 10,12 The fluorination of lithium sulfonimides ( 2a – c ) substituted by Ns/Ns, Ns/ p -Ns and Ns/Ms (methanesulfonyl) groups was carried out by using N 2 -diluted F 2 (2 vol%) in acetonitrile/H 2 O at 0 °C, affording the corresponding products 1a – c in high yields (84–99%) (Scheme 2a). Lithium salt 2f , readily prepared from commercially available N -( tert -butoxycarbonyl)-2-nitrobenzenesulfonamide, was also converted to N -fluorinated product 1f under the same reaction conditions.…”

The advent of electrophilic hydroxylamine-derived reagents for the direct preparation of unprotected amines

“…Recent examples are Fier's reagent (R12) for alpha-carbamation of pyridines 29 and an improved version of NFSI by the Hashimoto group (NFC, R16). 178 In most cases, hydroxylamine-derived reagents exhibit scalable syntheses, air and temperature stability and a broad range of applications. Their practicality is further increased as they tend to be easy-to-handle solids with an extended shelf life.…”

“…Recent examples are Fier's reagent (R12) for alpha-carbamation of pyridines 29 and an improved version of NFSI by the Hashimoto group (NFC, R16). 178 …”

“…Year of their first reported application in brackets. [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] Reagents with known N-substituted congeners are marked with a dagger. Scheme 1 Unprotected, direct aziridination of alkenes.…”