Multi-faceted reactivity of N-fluorobenzenesulfonimide (NFSI) under mechanochemical conditions: fluorination, fluorodemethylation, sulfonylation, and amidation reactions

• José G. Hernández,
• Karen J. Ardila-Fierro,
• Dajana Barišić and
• Hervé Geneste

Beilstein J. Org. Chem. 2022, 18, 182–189, doi:10.3762/bjoc.18.20

• reagent [9][10][11], and phenylsulfonyl group transfer reagent [12][13]. In the field of mechanochemistry, the usefulness of N-fluorobenzenesulfonimide has been exemplified in the asymmetric fluorination of β-keto esters (Scheme 1a) [14], and in diastereoselective fluorinations (Scheme 1b) [15], which

Development of N-F fluorinating agents and their fluorinations: Historical perspective

• Teruo Umemoto,
• Yuhao Yang and
• Gerald B. Hammond

Beilstein J. Org. Chem. 2021, 17, 1752–1813, doi:10.3762/bjoc.17.123

• -dichlorocamphorsultam) 17-2 [75] (Scheme 37). The maximum enantioselectivity of enolates of β-ketoesters with (−)-9-1 or (+)-9-2, first prepared by Lang in 1988 (see section 1-9), was 70% ee. The asymmetric fluorination with (+)- or (−)-17-2 afforded up to 75% ee as indicated in Scheme 38. The dichloro reagent 17-2

• reagent 27-2 in good to high yields [90]. In addition, Takeuchi et al. reported that optically active N-fluorosultams, (R)- and (S)-N-fluoro-3-cyclohexyl-3-methyl-2,3-dihydrobenzo[1,2-d]isothiazole 1,1-dioxides 27-6 (Scheme 61) were efficient reagents for the asymmetric fluorination of enolates [91]. To

• 'R)-isomer 28-7a and (2'S,3S,5'R)-isomer 28-7b in 81% and 44% yield, respectively. Figure 9 summarizes the outcomes of asymmetric fluorination reactions of enolates of aryl ketones using 28-7a and -7b. In the event isomer 28-7a yielded much better ees than 28-7b. Although 28-7a gave a maximum 70% ee

Recent advances in transition-metal-catalyzed incorporation of fluorine-containing groups

• Xiaowei Li,
• Xiaolin Shi,
• Xiangqian Li and
• Dayong Shi

Beilstein J. Org. Chem. 2019, 15, 2213–2270, doi:10.3762/bjoc.15.218

• derivatives. Notably, in this process, a new method was developed for generating Ag[18F]F by using a sep-pak cartridge. In 2012, van Leeuwen and co-workers [45] described the synthesis of new enantiopure wide-bite-angle diphosphanes and their application in the asymmetric fluorination of α-cyanoacetates with

• described a similar method for the asymmetric fluorination of racemic allylic trichloroacetimidates utilizing a chiral bicyclo[3.3.0]octadiene-ligated iridium complex (Scheme 45b) [93]. This reaction proceeded under mild conditions with an extremely broad substrate scope, as well as excellent branched-to

• ). Remarkably, this was the first example to afford (Z)-allyl fluorides (Z:E ratio > 20:1). In 2015, Nguyen et al. [95] explored the asymmetric fluorination of racemic, secondary allylic trichloroacetimidates with Et3N·3HF using a chiral-diene-ligated Ir complex (Scheme 47). This process proceeded under mild

Recent advances in hypervalent iodine(III)-catalyzed functionalization of alkenes

• Xiang Li,
• Pinhong Chen and
• Guosheng Liu

Beilstein J. Org. Chem. 2018, 14, 1813–1825, doi:10.3762/bjoc.14.154

• aminofluorination of alkenes [62]. Catalytic difluorination of alkenes with Selectfluor [63]. Iodoarene-catalyzed 1,2-difluorination of alkenes [64]. Iodoarene-catalyzed asymmetric fluorination of styrenes [64][65]. Gem-difluorination of styrenes [67]. Asymmetric gem-difluorination of cinnamic acid derivatives [68

Organocatalytic asymmetric fluorination of α-chloroaldehydes involving kinetic resolution

• Kazutaka Shibatomi,
• Takuya Okimi,
• Yoshiyuki Abe,
• Akira Narayama,
• Nami Nakamura and
• Seiji Iwasa

Beilstein J. Org. Chem. 2014, 10, 323–331, doi:10.3762/bjoc.10.30

• enantioselective α-fluorination of racemic α-chloroaldehydes with a chiral organocatalyst yielded the corresponding α-chloro-α-fluoroaldehydes with high enantioselectivity. It was also revealed that kinetic resolution of the starting aldehydes was involved in this asymmetric fluorination. This paper describes the

• determination of the absolute stereochemistry of a resulting α-chloro-α-fluoroaldehyde. Some information about the substrate scope and a possible reaction mechanism are also described which shed more light on the nature of this asymmetric fluorination reaction. Keywords: α-branched aldehyde; asymmetric

• (Scheme 1) [8]. These results suggested that kinetic resolution of the starting aldehydes was involved in this asymmetric fluorination. To collect further information on the reaction mechanism, we sought to determine the absolute configuration of 4a. Recently, we reported the enantioselective synthesis of

Recyclable fluorous cinchona alkaloid ester as a chiral promoter for asymmetric fluorination of β-ketoesters

• Wen-Bin Yi,
• Xin Huang,
• Zijuan Zhang,
• Dian-Rong Zhu,
• Chun Cai and
• Wei Zhang

Beilstein J. Org. Chem. 2012, 8, 1233–1240, doi:10.3762/bjoc.8.138

• , Boston, MA 02125, USA 10.3762/bjoc.8.138 Abstract A fluorous cinchona alkaloid ester has been developed as a chiral promoter for the asymmetric fluorination of β-ketoesters. It has comparable reactivity and selectivity to the nonfluorous versions of cinchona alkaloids and can be easily recovered from

• the reaction mixture by simple fluorous solid-phase extraction (F-SPE) and used for the next round of reaction without further purification. Keywords: asymmetric fluorination; β-ketoester; fluorous cinchona ester; organocatalysis; recyclable chiral promoter; Introduction Fluorinated organic

• electrophilic reaction with Selectfluor (F-TEDA-BF4, 1-chloromethyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate)), as developed by Bank [7][8][9]. The Cahard [10][11][12] and Shibata [13][14] groups combined cinchona alkaloids and Selectfluor for asymmetric fluorination of substrates such as

Development of the titanium–TADDOLate-catalyzed asymmetric fluorination of β-ketoesters

• Lukas Hintermann,
• Mauro Perseghini and
• Antonio Togni

Beilstein J. Org. Chem. 2011, 7, 1421–1435, doi:10.3762/bjoc.7.166

• reactions were developed, before Differding and Lang found the first stoichiometric asymmetric fluorination of β-ketoester enolates with a chiral N–F (N-fluoroamine) reagent in 1988 [21]. Later work by Davis [22][23], Takeuchi [24] and their respective coworkers extended this chemistry, while Haufe and

• asymmetric fluorination Having shown the viability of Lewis acid catalyzed fluorination, we focused on the development of an asymmetric catalytic fluorination reaction using enantiopure Lewis acid catalysts. Based on the screening results (Scheme 3), titanium or aluminum catalysts were logical choices. An

• 6), the reagents induced similar enantioselectivity. Ligand variations in the asymmetric titanium-catalyzed fluorination reaction We tested several chiral diols in the titanium-catalyzed asymmetric fluorination, but notable success was only achieved with TADDOL ligands [91]. We obtained several

DBFOX- Ph/metal complexes: Evaluation as catalysts for enantioselective fluorination of 3-(2-arylacetyl)-2-thiazolidinones

• Takehisa Ishimaru,
• Norio Shibata,
• Dhande Sudhakar Reddy,
• Takao Horikawa,
• Shuichi Nakamura and
• Takeshi Toru

Beilstein J. Org. Chem. 2008, 4, No. 16, doi:10.3762/bjoc.4.16

• ]. They mentioned in the paper that a binary system consisting of Ni(OTf)2–binap complex and 2,6-lutidine failed to promote asymmetric fluorination. We also briefly attempted the fluorination of 1a using the (S,S)-Box-Ph ligand instead of DBFOX-Ph. While the Box-Ph/Cu(OTf)2 catalyst was not effective (run

• availability of commonly used classes of ligands for asymmetric catalysis, such as, TADDOLs [37][39][41][47], BINAPs [38][40][43][44][46][49][51][53][55][56][57] and bis(oxazoline) [33][34][36][42][45]. Of particular importance are BINAP ligands. Sodeoka et al. have used the latter ligands in asymmetric

• fluorination of a wide range of substrates, including β-keto esters, β-keto phosphonates, oxindoles [38][40][43][51][53][56][57]. They have also recently reported the enantioselective fluorination of 3-(2-arylacetyl)-2-thiazolidinones with their extended catalytic system, NiCl2-BINAP/R3SiOTf-lutidine with high