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

Electrophilic aromatic substitution of electron-rich arenes with N-fluorobenzenesulfonimide (NFSI) as an electrophile

An efficient amidation of electron-rich arenes using NFSI as a nitrogen source has been successfully disclosed. This amidation process can be easily conducted at elevated temperatures, without the need for catalysts or additives. A wide range of arenes substituted with hydroxy, alkoxy, or carbonyl groups were found to be compatible, yielding the desired amination products. Computational study shows that the amidation proceeds via an electrophilic aromatic substitution pathway, comprising a three-step process that includes substitution, addition, and elimination, which differs slightly from the classical mechanism.

Copper-Catalyzed Intermolecular Cross-dehydrogenative C-N Coupling at Room Temperature via Remote Activating Group Enabled Radical Relay Strategy

Employing N-fluorobenzenesulfonimide (NFSI) as a nitrogen-centered radical (NCR) precursor, an intermolecular C(sp²)-N coupling on heteroarenes or substituted benzenes with remote activated aniline derivatives via copper catalyzed N-N radical relay strategy at room temperature is developed. Good to excellent yields are acquired, and no ligand or additive is required. Reaction scope investigation and preliminary mechanistic studies demonstrate that the remote activating strategy and delicate control on the reactivities of active NCR species are essential to guarantee satisfactory chemo- and site-selectivity.

Conversion of a AuI Fluorido Complex into an N-Fluoroamido Derivative: N-F versus Au-N Reactivity

The Au^I complex [Au{N(F)SO₂ Ph}(SPhos)] (SPhos=dicyclohexyl(2',6'-dimethoxy[1,1'-biphenyl]-2-yl)phosphane) (2) bearing a fluoroamido ligand has been synthesized by reaction of the fluorido complex [Au(F)(SPhos)] (1) with NFSI (NFSI=N-fluorobenzenesulfonimide). A reaction with CO resulted in an unprecedented insertion into the N-F bond at 2. With the carbene precursor N₂ CH(CO₂ Et) N-F bond cleavage gave the Au-F bond insertion product [Au{CHF(CO₂ C₂ H₅ )}(SPhos)] (7). The presence of CNtBu led to Au-N cleavage at 2 and concomitant amide formation to give the cationic complex [Au(CNtBu)(SPhos)][N(F)SO₂ Ph)] (5), which reacted further to give FtBu as well as the cyanido complex [Au(CN)(SPhos)] (6). These results led to the development of a process for the amination of electrophilic organic substrates by transfer of the fluoroamido group NF(SO₂ Ph)^- .

Direct Benzylic C(sp3)-O Coupling with Alcohol via Site-Selective C(sp3)-H Cleavage at Room Temperature through a Remote Directing Group-Enabled Radical Relay Strategy

Employing a low loading of the terminal oxidant, a remote directing group-enabled radical relay strategy for benzylic direct C(sp³)-H alkoxylation with alcohols at room temperature is developed. Satisfactory site-selectivity, chemoselectivity, and reaction scope are achieved under simple and mild conditions, and no ligand or additive is required. Mechanistic studies, ready conversions of the directing group, and other benzylic functionalizations currently under development in our laboratory further indicate the promising potentials of this remote directing group-enabled radical relay strategy.

Remote carbamate-directed site-selective benzylic C–H oxygenation via synergistic copper/TEMPO catalysis at room temperature

A benzylic C(sp3)–H oxygenation with water at room temperature through a ligand- and additive-free synergistic copper/TEMPO-catalysed radical relay pathway and a remote directing strategy is described.

C–N coupling reactions with arenes through C–H activation: the state-of-the-art versus the principles of green chemistry

Herein, we discuss the state-of-the-art in arene C–N coupling through C–H activation and to what extent it complies with the principles of green chemistry, with a focus on heterogeneously catalysed systems.

Visible-light enabled room-temperature dealkylative imidation of secondary and tertiary amines promoted by aerobic ruthenium catalysis

Employing sulfonyl azide as a nitrogen donor, a visible-light-enabled aerobic dealkylative imidation of tertiary and secondary amines involving C(sp³)–C(sp³) bond cleavage with moderate to excellent yields at room temperature is described. It has been demonstrated that this imidation could take place spontaneously upon visible-light irradiation, and could be facilitated considerably by a ruthenium photocatalyst and oxygen. An alternative mechanism to the previous aerobic photoredox pathway has also been proposed.

A photoredox dealkylative imidation of tertiary and secondary amines with sulfonyl azide facilitated by aerobic ruthenium-catalysis to afford sulfonyl amidine at room temperature is reported.

Synergetic copper/TEMPO-catalysed benzylic C–H imidation with N-fluorobenzenesulfonimide at room temperature and tandem conversions with alcohols or arenes

A remote carbamate-directed benzylic C–H imidation with NFSI at room temperature through synergetic CuCl-TEMPO catalysis and tandem alkoxylation or arylation with alcohols or arenes are described.

Exploring the behavior of the NFSI reagent as a nitrogen source

The diverse biological activities of nitrogen-containing compounds make the construction of the C-N bond of great importance. As N-fluorobenzenesulfonimide, one of the most abundant chemical feedstock, has a dual behaviour, i.e. as an electrophilic fluorination and amidation source, it attracts the attention of synthetic chemists for exploitation. This review comprehensively summarizes the significant progress of the efficient and mild amidation reactions, with an emphasis on approaches for the generation of nitrogen-centered intermediates, related mechanisms and new synthetic chemistry methods that offer opportunities to overcome obstacles in pharmaceutical applications. In this perspective, we discuss the developments in the amidation reaction using NFSI in the past decade. We discuss the recent progress, challenges and future outcomes in the area of amidation chemistry using commercially available NFSI.

Synthesis and Reactions of 3,3-Difluoro-2-exo-methylidene Indolines

A dearomative electrophilic fluorination of 2-methylindoles is reported, delivering 3,3-difluoroindolines bearing an exomethylidene. The model substrate was synthesized on up to a 20 mmol scale and was purified by a practical recrystallization as a crystalline bench-stable, yet reactive solid. The olefin is amphoteric and can react both as a nucleophile and as an electrophile. A wide range of metal-free, palladium, rhodium, and copper reactions was explored, forming new C–H, C–B, C–C (alkyl and aryl), C–N, C–O, C–P, and C–S bonds.

N-Fluorobenzenesulfonimide: a useful and versatile reagent for the direct fluorination and amination of (hetero)aromatic C–H bonds

This review updates recent advances and developments in the direct fluorination and amination of (hetero)aromatic C–H bonds utilizing N-fluorobenzenesulfonimide, classified according to the type of catalyst.

This review updates recent advances and developments in the direct fluorination and amination of (hetero)aromatic C–H bonds utilizing N-fluorobenzenesulfonimide, classified according to the type of catalyst.

Nickel-promoted C(2)–H amidation of quinoline N-oxides with N-fluorobenzenesulfonimide

The first example of nickel-promoted C–H amidation of quinoline N-oxides with NFSI.

Efficient metal-free aminoiodination of alkenes with N-fluorobenzenesulfonimide under mild conditions

A novel regioselective and stereoselective transition-metal-free aminoiodination of alkenes through an iodonium intermediate using NFSI as both the oxidant and amino precursor under mild conditions with a broad alkene scope is disclosed.

Metal-free C–H amination of arene with N-fluorobenzenesulfonimide catalysed by nitroxyl radicals at room temperature

The first C–H amination of arene with NFSI via organocatalysis is disclosed, which can be achieved at room temperature with a broad substrate scope.

NFSI-participated intermolecular aminoazidation of alkene through iron catalysis

An iron-catalysed intermolecular vicinal aminoazidation of alkene with NFSI is reported, with broader alkene scope comparing to previously reported aminoazidation.