N-Fluorobenzenesulfonimide (NFSI)

N-Fluorobenzenesulfonimide is a mild electrophilic fluorinating reagent, that can also be used as a strong oxidant for the promotion of reductive elimination from transition metals.

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Recent Literature

Orangoselenium catalysis enables an efficient route to 3-amino allylic alcohols in excellent regio- and stereoselectivity in the presence of a base. In the absence of bases α,β-unsaturated aldehydes were formed in excellent yield. The hydroxy group is crucial for the direct amination.
Z. Deng, J. Wei, L. Liao, H. Huang, X. Zhao, Org. Lett., 2015, 17, 1834-1837.

A highly diastereoselective Pd-catalyzed carbonyl allylation of aldehydes and isatins with simple acyclic olefins as allylating reagents consists of a Pd-catalyzed oxidative allylic C-H borylation and an allylboration of carbonyls accelerated by phosphoric acid. N-Fluorobenzenesulfonimide as oxidant plays a key role.
Z.-L. Tao, X.-H. Li, Z.-Y. Han, L.-Z. Gong, J. Am. Chem. Soc., 2015, 137, 4054-4057.

Cu(acac)₂ catalyzes an unprecedented N-demethylation of N-methyl amides in the presence of N-fluorobenzenesulfonimide as an oxidant. The reaction involves carbinolamines as intermediates, that spontaneously decompose to N-demethylated amides and formaldehyde, because of their inherent instability.
X. Yi, S. Lei, W. Liu, F. Che, C. Yu, X. Liu, Z. Wang, X. Zhou, Y. Zhang, Org. Lett., 2020, 22, 4583-4587.

The combination of silyl radical-mediated halogen-atom abstraction and benzophenone photosensitization enables a fluorination of alkyl bromides. Selectivity for halogen-atom abstraction over Si-F bond formation is observed in the presence of an electrophilic fluorinating reagent containing a weak N-F bond.
G. H. Lovett, S. Chen, X.-S. Xue, K. N. Houk, D. W. C. MacMillan, J. Am. Chem. Soc., 2019, 141, 20031-20036.

A Cu-catalyzed C-H fluorination with N-fluorobenzenesulfonimide (NFSI), followed by substitution of the resulting fluoride with various nucleophiles, enables a site-selective transformation of benzylic C-H bonds into diverse functional groups.
A. Vasilopoulos, D. L. Golden, J. A. Buss, S. S. Stahl, Org. Lett., 2020, 22, 5746-5748.

Planar chiral [2.2]paracyclophane-based isothiourea catalysts catalyze a highly efficient enantioselective fluorination of carboxylic acids to provide a broad range of optically active α-fluoroesters in high yield and excellent enantioselectivity.
S. Yuan, C. Liao, W.-H. Zheng, Org. Lett., 2021, 23, 4142-4146.

A catalytic asymmetric coupling of aryl alkyl ketenes with commercially available N-fluorodibenzenesulfonimide (NFSI) and C₆F₅ONa furnishes tertiary α-fluoroesters. Mechanistic studies suggest that the addition of an external nucleophile (C₆F₅ONa) is critical for turnover, releasing the catalyst from an N-acylated intermediate.
S. Y. Lee, S. Neufeind, G. C. Fu, J. Am. Chem. Soc., 2014, 136, 8899-8902.

Functionalized aryl- or heteroarylmagnesium reagents, prepared from the corresponding bromides or iodides using halogen-magnesium exchange or direct magnesium insertion in the presence of lithium chloride, reacted smoothly with N-fluorobenzenesulfonimide to give the corresponding aromatic fluorides in good yields.
S. Yamada, P. Knochel, Synthesis, 2010, 2490-2494.

A transition-metal-free coupling of esters with geminal bis(boron) compounds provides an α,α-bis(enolate) equivalent which can be trapped with electrophiles including alkyl halides and fluorinating agents. This presents an efficient, convergent synthetic strategy for the synthesis of α,α-difunctionalized ketones.
C. E. Iacono, T. C. Stephens, T. S. Rajan, G. Pattison, J. Am. Chem. Soc., 2018, 140, 2036-2040.

A copper-catalyzed oxidative cleavage reaction of terminal and internal alkynes using NFSI and TBHP provides aryl ketone products in good yields. NFSI not only functioned as N-centered radical precursor but also engaged in the aryl group migration. Mechanistic studies also suggested the important role of water.
L. Tang, F. Yang, H. Cheng, C. Tan, C. Jin, H. Chen, Y. Huang, S. Zhang, S. Zhang, W. Song, J. Tan, Org. Lett., 2020, 22, 8618-8623.

A vanadium-catalyzed coupling of allenylic alcohols with electrophilic halide sources provides α-halo-α',β'-unsaturated ketones. Fluorine, chlorine, and bromine electrophiles can be utilized, and the resulting products can give rise to the introduction of nitrogen, oxygen, sulfur, and iodine nucleophiles α to the ketone through substitution chemistry.
B. M. Trost, J. S. Tracy, T. Yusoontorn, Org. Lett., 2019, 21, 1207-1211.

An isothiourea-catalyzed fluorination of alkynyl-substituted acetic acids provides a broad range of optically active tertiary α-alkyl fluorides in high enantioselectivity (up to 97% ee). Furthermore, this methodology can be scaled up to a Gram scale without loss of enantioselectivity.
S. Yuan, W.-H. Zheng, J. Org. Chem., 2022, 87, 713-720.

With a suitable combination of N-heterocyclic carbene precatalyst, base, and fluorine reagent, a fluorination of alkynals proceeded smoothly to yield a wide range of α-fluoroallenoates with excellent chemoselectivity. α-Fluorinated allenoates are versatile synthetic intermediates toward other useful fluorine-containing building blocks.
X. Wang, Z. Wu, J. Wang, Org. Lett., 2016, 18, 576-579.

An organocatalytic system of L-proline and salicylic acid enables a highly stereoselective synthesis of α,α-difluoro-γ,γ-disubstituted butenals. The reaction offers a wide substrate scope and excellent E stereoselectivity in most cases.
S. Arimitsu, M. Nakasone, J. Org. Chem., 2016, 81, 6707-6713.

Orangoselenium catalysis enables an efficient route to 3-amino allylic alcohols in excellent regio- and stereoselectivity in the presence of a base. In the absence of bases α,β-unsaturated aldehydes were formed in excellent yield. The hydroxy group is crucial for the direct amination.
Z. Deng, J. Wei, L. Liao, H. Huang, X. Zhao, Org. Lett., 2015, 17, 1834-1837.

The copper-catalyzed ring-opening of arylcyclopropanes in the presence of N-fluorobis(arenesulfonyl)imides and (2,2′-bipyridine)Zn(CF₃)₂ affords γ-trifluoromethylated amines in good yields at room temperature.
H. Zhang, H. Xiao, F. Jiang, Y. Fang, L. Zhu, C. Li, Org. Lett., 2021, 23, 2268-2272.

Depending on the steric hindrance of the ligand, a regioselective palladium-catalyzed diamination of unactivated alkenes, provides either amino-functionalized piperidines or pyrrolidines. 6-Endo diamination occurred with a less sterically hindered quinox ligand to afford 3-aminopiperidines, while 5-exo diamination occurred with a bulky pyox ligand to give amino-substituted pyrrolidines.
X. Liu, C. Hou, Y. Peng, P. Chen, G. Liu, Org. Lett., 2020, 22, 9371-9375.

A new selenium-catalyzed protocol for the direct, intramolecular amination of C(sp²)-H bonds of ortho-vinyl anilines and vinylated aminopyridines using N-fluorobenzenesulfonimide as the terminal oxidant enables the facile formation of a broad range of diversely functionalized indoles and azaindoles, respectively. Key factor is the pronounced carbophilicity of selenium electrophiles for the catalytic activation of alkenes.
S. Ortgies, A. Breder, Org. Lett., 2015, 17, 2748-2751.

The use of N-fluorobenzenesulfonimide (NFSI) enables an efficient, simple, and metal-free fluorination of 2H-indazoles in water under ambient air. This transformation provides direct access to fluorinated indazole derivatives with broad functionalities in good yields. The experimental results suggest a radical mechanistic pathway.
P. Ghosh, A. Hajra, J. Org. Chem., 2021, 86, 10883-10888.

The use of the commercially available N-fluorobenzenesulfonimide (NFSI) as an amination reagent enables a copper-catalyzed aminative aza-annulation of enynyl azide to provide amino-substituted nicotinate derivatives in a single step in good yield.
C. R. Reddy, S. K. Prajapti, R. Ranjan, Org. Lett., 2018, 20, 3128-3131.

An efficient organoselenium-catalyzed aza-Wacker reaction of olefinic hydrazones and oximes provides isoquinolinium imides and an isoquinoline N-oxides. This transformation involves a direct intramolecular C-H amination.
H. Li, L. Liao, X. Zhao, Synlett, 2019, 30, 1688-1692.