N-fluorobenzenesulfonimide Research Articles

Gold‐Catalyzed Dehydrogenative Cycloisomerization of 1,4‐Enyne Esters to 3,5‐Disubstituted Phenol Derivatives

AbstractA method to prepare synthetically important 3,5‐disubstituted phenol derivatives that relies on the sequential gold(I)‐catalyzed dehydrogenative cycloisomerization of 1,4‐enyne esters in the presence of 2,3‐dichloro‐5,6‐dicyanobenzoquinone (DDQ) or N‐fluorobenzenesulfonimide (NFSI) is described. The synthetic versatility of the methodology was exemplified by a gram‐scale reaction of one example, the ease to realize subsequent functional transformations of an adduct, and the application of the method to the synthesis of the bioactive molecule LUF5771.magnified image

Copper-Catalyzed Azidative Multifunctionalization of Alkynes.

A facile and efficient copper-catalyzed azidative multifunctionalization of alkynes has been developed by using N-fluorobenzenesulfonimide (NFSI) as both nitrogen source and aryl source and trimethylsilyl azide (TMSN3) as azido source. This transformation proceeds under mild conditions, providing a series of α-azido-α-aryl imine in good yields by a single operation starting from a wide range of alkynes. The prepared α-azido-α-aryl imines could be easily converted into 1,5-piperizine-fused 1,2,3-triazoles and azido enamines.

Trifluoromethylfluorosulfonylation of Unactivated Alkenes Using Readily Available Ag(O2 CCF2 SO2 F) and N-Fluorobenzenesulfonimide.

Presented is a novel intermolecular radical trifluoromethylfluorosulfonylation of unactivated alkenes under mild reaction conditions with good functional-group tolerance in the most atom-economic manner by using readily available Ag(O2 CCF2 SO2 F) and N-fluorobenzenesulfonimide (NFSI). Both the trifluoromethyl and sulfonyl groups in the products originate from Ag(O2 CCF2 SO2 F).

Trifluoromethylfluorosulfonylation of Unactivated Alkenes Using Readily Available Ag(O2CCF2SO2F) and N‐Fluorobenzenesulfonimide

AbstractPresented is a novel intermolecular radical trifluoromethylfluorosulfonylation of unactivated alkenes under mild reaction conditions with good functional‐group tolerance in the most atom‐economic manner by using readily available Ag(O2CCF2SO2F) and N‐fluorobenzenesulfonimide (NFSI). Both the trifluoromethyl and sulfonyl groups in the products originate from Ag(O2CCF2SO2F).

Iron‐catalyzed C(5)−H Imidation of Azole with N‐Fluorobenzenesulfonimide

AbstractAn iron(II)‐catalyzed direct imidation of oxazole and thiazole with N‐fluorobenzenesulfonimide (NFSI) through C(5)−H bond cleavage is disclosed, providing C5‐imidated azoles in moderate to excellent yields with broad substrate scope. This reaction represents the first iron‐catalyzed C−H imidation of arene where NFSI serves as the imidation reagent, and potentially constitutes an efficient access to C5‐functionalized azole with great medicinal significance.magnified image

Electrophilic Fluorination with 1-Fluoro-2,4,6- trimethylpyridinium tetrafluoroborate and NFSI (N-Fluorobenzenesulfonimide) reagents directed towards the synthesis of heterocycles ; Current Trends

Electrophilic Fluorination with 1-Fluoro-2,4,6- trimethylpyridinium tetrafluoroborate and NFSI (N-Fluorobenzenesulfonimide) reagents directed towards the synthesis of heterocycles ; Current Trends

Decarboxylative fluorination of β-Ketoacids with N-fluorobenzenesulfonimide (NFSI) for the synthesis of α-fluoroketones: Substrate scope and mechanistic investigation

Cesium carbonate (Cs2CO3)-mediated decarboxylative fluorination of β-ketoacids using NFSI in the MeCN/H2O mixed solvent system affords α-fluoroketones with a broad scope. Both electron-rich and electron-deficient α-non-substituted β-ketoacids are amenable to this protocol. The mechanistic study indicates that the reaction proceeds through electrophilic fluorination followed by decarboxylation, which is different from the decarboxylative fluorination of normal carboxylic acids.

α-Quaternary Mannich Bases through Copper-Catalyzed Amination-Induced 1,2-Rearrangement of Allylic Alcohols.

A novel copper-catalyzed amination-induced 1,2-rearrangement reaction of allylic alcohols has been developed under simple and mild conditions. The commercially available N-fluorobenzenesulfonimide (NFSI) is employed as an amination reagent. In this transformation, not only alkyl, but also aryl substituents can efficiently undergo 1,2-carbon atom migration, thereby providing an efficient and powerful route to prepare a wide range of α-quaternary Mannich bases. The reaction features a broad substrate scope, operational simplicity, and excellent practicality.

Sulfoxidation of alkenes and alkynes with NFSI as a radical initiator and selective oxidant.

Sulfoxides are important functional molecules. We develop a short-route (one-pot) synthesis of this class of molecules by reacting thiols with alkenes or alkynes under mild and metal-free conditions. N-Fluorobenzenesulfonimide (NFSI) is used to play dual roles: as a radical initiator for a thiol-ene/-yne reaction to form sulfide adducts, and as efficient oxidant for conversion of the sulfides formed in situ to sulfoxides. Over-oxidation of the sulfoxides to sulfones is avoided in our approach.

Cu-Catalyzed aromatic C-H imidation with N-fluorobenzenesulfonimide: mechanistic details and predictive models.

The LCuBr-catalyzed C-H imidation of arenes by N-fluorobenzenesulfonimide (NFSI), previously reported by us, utilizes an inexpensive catalyst and is applicable to a broad scope of complex arenes. The computational and experimental study reported here shows that the mechanism of the reaction is comprised of two parts: (1) generation of the active dinuclear CuII-CuII catalyst; and (2) the catalytic cycle for the C-H bond imidation of arenes. Computations show that the LCuIBr complex used in experiments is not an active catalyst. Instead, upon reacting with NFSI it converts to an active dinuclear CuII-CuII catalyst that is detected using HRMS techniques. The catalytic cycle starting from the CuII-CuII dinuclear complex proceeds via (a) one-electron oxidation of the active catalyst by NFSI to generate an imidyl radical and dinuclear CuII-CuIII intermediate, (b) turnover-limiting single-electron-transfer (SET1) from the arene to the imidyl radical, (c) fast C-N bond formation with an imidyl anion and an aryl radical cation, (d) reduction of the CuII-CuIII dinuclear intermediate by the aryl radical to regenerate the active catalyst and produce an aryl-cation intermediate, and (e) deprotonation and rearomatization of the arene ring to form the imidated product. The calculated KIE for the turnover-limiting SET1 step reproduces its experimentally observed value. A simple predictive tool was developed and experimentally validated to determine the regiochemical outcome for a given substrate. We demonstrated that the pre-reaction LCuX complexes, where X = Cl, Br and I, show a similar reactivity pattern as these complexes convert to the same catalytically active dinuclear CuII-CuII species.

Copper-catalyzed oxidative amidation of α,β-unsaturated ketones via selective C–H or C–C bond cleavage

The copper-catalyzed oxidative amidation of α,β-unsaturated ketones with N-fluorobenzenesulfonimide (NFSI) via a highly regioselective cleavage of C(CO)–C(vinyl) or C(vinyl)–H bonds of ketones has been achieved.

Copper‐Catalyzed Remote C−H Amination of Quinolines with N‐Fluorobenzenesulfonimide

AbstractA copper‐catalyzed remote C−H amination of 8‐aminoquinoline scaffolds on the C5 position is described. The protocol employs commercially available N‐fluorobenzenesulfonimide (NFSI) as the amination reagent and shows broad substrate scope, providing various 5‐aminated quinolines in moderate to excellent yields under mild conditions. These reactions feature complete regioselectivity, operational simplicity, and high efficiency.magnified image

Copper-Catalyzed Radical-Promoted Aminocyclization of Acrylamides with N-Fluorobenzenesulfonimide.

A facile copper-catalyzed radical aminoarylation of acrylamide with N-fluorobenzenesulfonimide (NFSI) is described. In the presence of copper acetate and 1,10-phenanthroline, a range of isoquinoline-1,3-diones can be constructed in moderate to good yields using NFSI as the amination reagent. Mechanistic studies demonstrated the reaction went through a sequential radical addition and cyclization pathway, which was supported by DFT calculations.

ChemInform Abstract: Transition‐Metal‐Free Fluoroarylation of Diazoacetamides: A Complementary Approach to 3‐Fluorooxindoles.

An efficient transition-metal-free fluoroarylation reaction of N-aryl diazoacetamides with NFSI (N-fluorobenzenesulfonimide) is described. This reaction directly provides 3-fluorooxindole derivatives in yields of 67–93% with high selectivity via a carbene-free process under mild reaction conditions.

Lewis acid-assisted N-fluorobenzenesulfonimide-based electrophilic fluorine catalysis in Beckmann rearrangement

A microwave-assisted N-fluorobenzenesulfonimide (NFSI)/Lewis acid-catalyzed Beckmann rearrangement was developed. The remarkable promotion to the electrophilicity of NFSI by Lewis acids was illustrated utilizing a series of readily available oxime substrates. The action model between NFSI and Lewis acids was probed by control experiments and theoretical calculations.

The Highly Regioselective Halogenation of N‐(8‐quinolinyl)amides on the C‐5 Position with Cuprous Halides Under Mild Conditions

AbstractRegioselective halogenation of heteroaromatics via C−H activation is a challenge in organic synthesis. In this paper, we described a simple, mild and highly selective protocol for halogenating C‐5 of N‐(8‐quinolinyl) amides with cuprous halides in the presence of NFSI (N‐Fluorobenzenesulfonimide) at room temperature. The different chloro‐, bromo‐ and iodo‐ substituted N‐(8‐quinolinyl) amides on C‐5 position were obtained respectively in good yields with excellent substrates tolerance.

ChemInform Abstract: Copper‐Catalyzed Decarboxylative Stereospecific Amidation of Cinnamic Acids with N‐Fluorobenzenesulfonimide.

An efficient copper-catalyzed decarboxylative coupling of cinnamic acids with N-fluorobenzenesulfonimide (NFSI) to give the corresponding substituted (E)-amination products stereospecifically is demonstrated. This new method is efficient and practical, and the corresponding products were obtained in moderate to good yields. The present protocol should broaden the scope of the decarboxylative cross-coupling reactions and provide a useful strategy for the construction of C–N bonds.

Metal‐Free Oxidative C−H Amination of 8‐Acylaminoquinolines and Anilides with N‐Fluorobenzenesulfonimide

AbstractAn oxidative C−H amination of 8‐acylaminoquinolines and anilides with N‐fluorobenzenesulfonimide (NFSI) has been developed. This process was mediated by a hypervalent iodine reagent PhI(OPiv)2 under mild reaction conditions without any metallic catalyst or oxidant. The protocol showed good air and moisture tolerance, functional groups compatibility, and gave the highly site‐selective amination products in moderate to good yields, providing a novel and facile method for synthesis of arylamine compounds.

ChemInform Abstract: Investigation of Meyer—Schuster Rearrangement Promoted by a Samarium(III) Triflate/N‐Fluorobenzenesulfonimide Lewis Acid System.

AbstractAn acceleration effect is observed when catalytic amounts of N‐fluorobenzenesulfonimide is added to a microwave promoted samarium triflate catalyzed Meyer—Schuster rearrangement of propargylic alcohols.

Rhodium-Catalyzed Oxy-Aminofluorination of Diazoketones with Tetrahydrofurans and N-Fluorobenzenesulfonimide

We have developed a rhodium-catalyzed oxy-aminofluorination method for transformation of diazoketones. The reaction is based on addition of tetrahydrofuran derivatives and N-fluorobenzenesulfonimide (NFSI) to the diazoketone substrate. The reaction can be performed under mild conditions with high regioselectivity. The synthetic scope involves a wide variety of diazoketones and tetrahydrofuran derivatives. The reaction is supposed to proceed via a tetrahydrofuran based onium ylide intermediate, which is formed from rhodium-carbenoid.