N-Fluorobenzenesulfonimide (NFSI)

Technical Specifications

Product Description & Scientific Applications

N-Fluorobenzenesulfonimide (NFSI), (PhSO2)2NF, is a bench-stable N–F reagent with two modes of reactivity: its electrophilic N–F bond is a fluorine (F+) source, and its benzenesulfonimide fragment is a nitrogen source for oxidative carbon–nitrogen bond formation. It is a strongly electrophilic second-generation fluorinating reagent.

Applications

• NFSI + enolate — Enantioselective α-fluorination of carbonyls: an activated ketene enolate reacts with NFSI to give α-fluorinated carbonyl derivatives of natural products, including chemotherapeutics and antibiotics.
• NFSI + enolate — Organocatalytic asymmetric fluorination: with a tertiary-amine–thiourea catalyst, NFSI is the terminal electrophile in a 1,4-addition/dearomative-fluorination sequence, giving products in 72–95% yield with up to 99:1 d.r. and 98% ee, bearing adjacent tertiary and α-fluoro quaternary stereocentres.
• NFSI + active methine — α-Fluorination of 1,3-dicarbonyls: NFSI converts β-keto phosphonates to enantioenriched α-fluoro-β-keto phosphonates under chiral Lewis-acid catalysis (up to 91% ee), and fluorinates unprotected 3-substituted oxindoles to 3-fluoro-2-oxindoles (up to 98% yield, 99% ee), a route to MaxiPost.
• NFSI + aldehyde (enamine) — Organocatalytic α-fluorination of aldehydes: an imidazolidinone catalyst forms an enamine that reacts with NFSI to give α-fluoro aldehydes with high enantioselectivity (up to 99% ee).
• NFSI + heteroarene — Regioselective late-stage monofluorination of N-protected pyridones, fluorine introduced opposite the carbonyl.
• NFSI + silyl enol ether — Selective mono- and difluorination of silyl enol ethers, with NFSI and its acyl-modified variants.
• NFSI + arene — Directed aromatic C–H fluorination: a Pd(OAc)2–NFSI–TFA system gives ortho-selective monofluorination directed by aryl N-heterocyclic groups (quinoxaline, pyrazole, benzo[d]oxazole, pyrazine).
• NFSI + C–H (benzylic) — Copper-catalysed benzylic C(sp3)–H fluorination; the benzyl fluorides are electrophiles for cross-coupling, and changing the conditions switches the same Cu/NFSI system from C–N to C–F coupling.
• NFSI + boron — Copper(I)-mediated borofluorination: alkynes are converted to cis-(β-fluorovinyl)boronates by an (NHC)copper(I) boryl followed by NFSI, giving anti-Markovnikov products.
• NFSI + alkene (aminofluorination) — Vicinal aminofluorination of styrenes, with NFSI as the source of both nitrogen and fluorine: a palladium-catalysed variant gives vicinal fluoroamines with high regioselectivity; a copper-catalysed radical variant, with NFSI as both radical nitrogen and fluorine source, gives the opposite regioselectivity.
• NFSI + N (amination) — Catalytic imidation and C–H amination, NFSI as the nitrogen source for oxidative C–N bond formation: copper-mediated C–H amination of imidazopyridines, and palladium-catalysed allylic C–H amination of alkenes.
• NFSI + sulfinate — Fluorine source in one-pot syntheses of aryl sulfonyl fluorides — from aryl bromides via DABSO, or from aryl thianthrenium salts — giving SuFEx-relevant products.

Shipping Destinations

• EU & UK: Priority delivery, 2–5 business days.
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• EFTA Countries (DDP): 3–7 business days, duties and taxes prepaid.
• Worldwide: 7–14 business days, selected locations.