N-Fluorocinchonidinium tetrafluoroborate F-CD-BF4: purification and structure elucidation of this novel enantioselective electrophilic fluorinating agent

Cahard, Dominique; Audouard, Christophe; Plaquevent, Jean‐Christophe; Toupet, Loı̈c; Roques, Nicolas

doi:10.1016/s0040-4039(01)00017-x

Cited by 55 publications

(20 citation statements)

References 9 publications

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“…Selectfluor was used to prepare the N-fluoroammonium derivatives 23 a-d of cinchona alkaloids by transfer fluorination (Figure 3, Scheme 26). [66][67][68] The fluorinated reagents 23 a-d were tested in the enantioselective fluorination of the sodium enolate of 2-methyl-1-tetralone, providing the product in up to 98 % yield and with up to 50 % ee (Table 8). Higher enantioselectivities (up to 94 % ee) were later observed with modified N-fluoro cinchona alkaloids.…”

Section: Enantioselective Transformationsmentioning

confidence: 99%

Selectfluor: Mechanistic Insight and Applications

et al. 2004

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The replacement of hydrogen atoms with fluorine substituents in organic substrates is of great interest in synthetic chemistry because of the strong electronegativity of fluorine and relatively small steric footprint of fluorine atoms. Many sources of nucleophilic fluorine are available for the derivatization of organic molecules under acidic, basic, and neutral conditions. However, electrophilic fluorination has historically required molecular fluorine, whose notorious toxicity and explosive tendencies limit its application in research. The necessity for an electrophilic fluorination reagent that is safe, stable, highly reactive, and amenable to industrial production as an alternative to very hazardous molecular fluorine was the inspiration for the discovery of selectfluor. This reagent is not only one of the most reactive electrophilic fluorinating reagents available, but it is also safe, nontoxic, and easy to handle. In this Review we document the many applications of selectfluor and discuss possible mechanistic pathways for its reaction.

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Section: Enantioselective Transformationsmentioning

confidence: 99%

Selectfluor: Mechanistic Insight and Applications

et al. 2004

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“…In a mechanistic study it has been shown that N-fluorochinchona alkaloids are the reactive intermediates [79]. A related approach was recently reported by the Cahard group, who used preformed N-fluoro ammonium salts of cinchona alkaloids as fluorinating agents [80][81][82]. These salts were prepared, as described above, from a cinchona alkaloid and Selectfluor in acetonitrile.…”

Section: Fluorination Reactionsmentioning

confidence: 99%

Nucleophilic Substitution at Aliphatic Carbon

Berkessel

Gröger

2005

Asymmetric Organocatalysis

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“…The asymmetric version of reaction is also explored with new chiral N ‐fluoro quaternary ammonium salt of cinchonidine ( 1e ; F‐CD‐BF 4 , Figure ). As per limited reports, F‐CD‐BF 4 and Selectfluor have been reagent of choice for electrophilic fluorination . The only example pertains to Selectfluor‐mediated allystannation of aldehydes and imines was studied by Wong in 2002 .…”

Section: Introductionmentioning

confidence: 99%

“…As per limited reports, F-CD-BF 4 and Selectfluor have been reagent of choice for electrophilic fluorination. [23][24][25][26] The only example pertains to Selectfluor-mediated allystannation of aldehydes and imines was studied by Wong in 2002. 27 Although cinchona alkaloids have been used as a chiral source in indiumcatalysed asymmetric allylation of aldehydes with moderate enantioselectivity, 28 there is no report available on F-CD-BF 4 -catalysed asymmetric allylation of imine.…”

Section: Introductionmentioning

confidence: 99%

Electrophilic [N—F]⁺ catalysed asymmetric allylation of (E)‐N,1‐diphenylmethanimine

Sharma

2018

Chirality

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New efficient catalysts based on electrophilic N‐fluoro quaternary ammonium salts are reported for catalytic allylation of (E)‐N,1‐diphenylmethanimine. The chiral version of the catalyst based on cinchonidine (F‐CD‐BF4) shows high catalytic activity with approximately 94% ee and TOF (>800 h−1). The F‐CD‐BF4 is prepared from cinchonidine and Selectfluor by one‐step transfer fluorination.

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N-Fluorocinchonidinium tetrafluoroborate F-CD-BF4: purification and structure elucidation of this novel enantioselective electrophilic fluorinating agent

Cited by 55 publications

References 9 publications

Selectfluor: Mechanistic Insight and Applications

Selectfluor: Mechanistic Insight and Applications

Nucleophilic Substitution at Aliphatic Carbon

Electrophilic [N—F]⁺ catalysed asymmetric allylation of (E)‐N,1‐diphenylmethanimine

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N-Fluorocinchonidinium tetrafluoroborate F-CD-BF4: purification and structure elucidation of this novel enantioselective electrophilic fluorinating agent

Cited by 55 publications

References 9 publications

Selectfluor: Mechanistic Insight and Applications

Selectfluor: Mechanistic Insight and Applications

Nucleophilic Substitution at Aliphatic Carbon

Electrophilic [N—F]+ catalysed asymmetric allylation of (E)‐N,1‐diphenylmethanimine

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Electrophilic [N—F]⁺ catalysed asymmetric allylation of (E)‐N,1‐diphenylmethanimine