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

Abstract

The palladium-catalyzed aminofluorination of styrenes using novel N-fluorobenzenesulfonimide (NFSI) derivatives with deprotectable substituents, and the selective deprotection and transformation of the resulting products into amines under the mild reaction conditions...

Difluorination of heterobenzylic C–H bonds with N-fluoro-N-(fluorosulfonyl)carbamate (NFC)

“…In the 19 F-NMR spectrum, the peak corresponding to N–F shifted significantly upfield from −47 to −132 ppm, whereas the peak corresponding to SO 2 -Fremained almost unchanged. We also verified that the deprotonation of H-NFSO 2 Ar (Ar = 2-NO 2 C 6 H 4 ) 13 by one equivalent of KHMDS (potassium hexamethyldisilazide) caused an upfield shift of the N–F peak from −93 to −134 ppm (see the ESI†). These results imply the formation of N -alkoxycarbonylpyridinium species 10 bearing the N -fluoro- N -(fluorosulfonamide) anion ( − N(F)SO 2 F).…”

“…Even when the reaction time was prolonged and the amount of NFSI was increased, the selectivity did not improve. NFSI analogues 1a–c with Ns (2-nitrobenzenesulfonyl) as an electron-withdrawing substituent, which were recently reported by our group, 13 led to good yields in shorter reaction time; however, the reactions showed moderate selectivity for difluorination, and the N–F reagents were decomposed after 2 h (entries 2–4). N–F reagents 1d–e with 3,5-bis(trifluoromethyl) substituents attached to the benzenesulfonyl and benzoyl groups 14 decreased the di-F selectivity and reactivity (entries 5 and 6).…”