Nucleophilic acylation of arylfluorides catalyzed by imidazolidenyl carbene

Suzuki, Yumiko; Toyota, Tomonori; Imada, Fumie; Sato, Masayuki; Miyashita, Akira

doi:10.1039/b302062b

Cited by 69 publications

(31 citation statements)

References 11 publications

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“…23) Aroylation was presented as a new method to synthesize benzophenone derivatives from fluorobenzenes and benzaldehydes. The reaction mechanism is shown in Chart 2.…”

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confidence: 99%

Synthesis of Heterocyclic Compounds via Nucleophilic Aroylation Catalyzed by Imidazolidenyl Carbene

Suzuki

Toyota

Miyashita

et al. 2006

CHEMICAL & PHARMACEUTICAL BULLETIN

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Xanthones and acridones were synthesized from 3,4-difluoronitrobenzene and 2-fluorobenzaldehydes in two or three steps. The key step was nucleophilic aroylation catalyzed by imidazolidenyl carbene. The nucleophilic aroylation of 3,4-difluoronitrobenzene afforded 2,2-difluoro-4-nitrobenzophenones. The cyclization of the difluorobenzophenones with O-nucleophile and N-nucleophile yielded 3-nitroxanthones and 3-nitroacridones, respectively. Indazole, quinolino[2,3-b]quinoxaline, and thianaphtho[2,3-b]quinoxaline derivatives were also synthesized via nucleophilic aroylation of 2,3-dichloroquinoxaline followed by cyclization with nucleophiles.

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“…23) Aroylation was presented as a new method to synthesize benzophenone derivatives from fluorobenzenes and benzaldehydes. The reaction mechanism is shown in Chart 2.…”

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confidence: 99%

Synthesis of Heterocyclic Compounds via Nucleophilic Aroylation Catalyzed by Imidazolidenyl Carbene

Suzuki

Toyota

Miyashita

et al. 2006

CHEMICAL & PHARMACEUTICAL BULLETIN

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“…18 Previously, we reported on the use of the NHC-catalyzed aroylation of Cl-and sulfonyl substituted N-heteroarenes, 19 arylimidoyl chlorides, 20 and electron-deficient 4-fluorobenzenes 21 to afford keto derivatives, demonstrating the applicability of this transformation to a variety of N-heteroarenes. However, in these examples, the heteroarene substitution positions were limited to the carbons of those imine moieties bearing a leaving group, with any substitution at those carbon atoms not adjacent to the nitrogen atoms being unknown.…”

Section: Introductionmentioning

confidence: 99%

Nucleophilic Aroylation on Fluoroquinazolines Catalyzed by N-Heterocyclic Carbenes

Suzuki¹,

Tachikawa²,

Nakagawa³

2018

HETEROCYCLES

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-We report on the synthesis of 7-benzoyl-and 7-heteroaroylquinazolines from 7-fluoroquinazolines and aromatic aldehydes by N-heterocyclic carbene (NHC)-catalyzed nucleophilic aromatic substitution, showing that the NHC derived from 1,3-dimethylimidazolium iodide outperformed those originating from other azolium (e.g., thiazolium and triazolium) salts. Additionally, the developed methodology allowed the preparation of 5-and 8-aroylquinazolines from the corresponding fluoroquinazolines.

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“…[3][4][5][6][7][8][9][10][11] We recently reported a catalytic method leading to the synthesis of various cyanohydrins using N-heterocyclic carbene 2 prepared from 1,3-bis(2,4,6-trimethylphenyl)imidazolium chloride (1) and KOt-Bu as a nucleophilic catalyst in cyanosilylation reactions.12) Cyanohydrins and their trimethylsilyl ethers are versatile intermediates in organic synthesis, 13,14) but the instability of cyanohydrins and their trimethylsilyl ethers is sometimes problematic for further transformations. Therefore, the development of a one-pot cyanation-O-protection reaction with a stable protecting group is desirable.…”

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confidence: 99%

Cyano-Phosphorylation of Aldehydes Catalyzed by a Nucleophilic N-Heterocyclic Carbene

Fukuda

Maeda

Kondo

et al. 2006

CHEMICAL & PHARMACEUTICAL BULLETIN

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N-Heterocyclic carbenes prepared from imidazolium salts and bases, have been used mainly in transition metal-catalyzed reactions as ligands.1,2) However, their suitability as nucleophilic catalysts has been underdeveloped. [3][4][5][6][7][8][9][10][11] We recently reported a catalytic method leading to the synthesis of various cyanohydrins using N-heterocyclic carbene 2 prepared from 1,3-bis(2,4,6-trimethylphenyl)imidazolium chloride (1) and KOt-Bu as a nucleophilic catalyst in cyanosilylation reactions.12) Cyanohydrins and their trimethylsilyl ethers are versatile intermediates in organic synthesis, 13,14) but the instability of cyanohydrins and their trimethylsilyl ethers is sometimes problematic for further transformations. Therefore, the development of a one-pot cyanation-O-protection reaction with a stable protecting group is desirable. In 1983, the above one-pot reaction of carbonyl compounds with diethyl cyanophosphonate (DEPC) in the catalytic amount of lithium diisopropylamide has been reported by Shioiri et al. 15) Herein, we disclose the first catalytic method leading to the synthesis of various cyanohydrin-O-phosphonates using N-heterocyclic carbene 2 prepared from 1,3-bis(2,4,6-trimethylphenyl)imidazolium chloride (1) and KOt-Bu as a nucleophilic catalyst in cyano-phosphorylation reactions.The cyano-phosphorylation of various aldehydes 3-10 was performed as shown in Table 1. The aldehydes except for trans-cinnamaldehyde (9) were reacted with N-heterocyclic carbene 2 prepared from 5 mol% of the imidazolium chloride 1 and 4 mol% of KOt-Bu, and 1.2 mol eq of DEPC in THF, affording the corresponding cyanohydrin-O-phosphonates in good yields.16) A polar solvent such as DMF was also a suitable solvent (entry 5). The use of ketones such as acetophenone and methyl vinyl ketone afforded little or none of the desired products.In summary, N-heterocyclic carbene 2 was found to function as catalyst in cyano-phosphorylation reaction of aldehydes with DEPC. Ongoing efforts are focused on developing an asymmetric version 17,18) of this reaction with a chiral Nheterocyclic carbene. ExperimentalIR spectra were measured on a JASCO IR Report-100 diffraction grating IR spectrophotometer.1 H-(270 MHz) and 13 C-NMR (68 MHz) spectra were measured on a JEOL JNM-EX-270 NMR spectrometer. MS spectra were measured on a JEOL JMS-SX-102A instrument. Commercially available aldehydes and reagents were used without any purification. THF was distilled from Na/benzophenone ketyl under a nitrogen atmosphere. DMF was distilled from CaH 2 under reduced pressure. Silica gel column chromatography was performed on Fuji silysia PSQ 60B.Representative Procedure for the Cyano-Phosphorylation Reaction To a stirred solution of 1,3-bis(2,4,6-trimethylphenyl)imidazolium chloride (1) (5.1 mg, 15 mmol) in THF (1.0 ml) was added KOt-Bu (1.4 mg, 13 mmol) at rt and the mixture was stirred for 15 min at the same temperature. After dissolving the imidazolium chloride 1 completely, the mixture was cooled to 0°C. Then, benzaldehyde (6) (32.1 mg, 0.302 m...

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Nucleophilic acylation of arylfluorides catalyzed by imidazolidenyl carbene

Abstract: Imidazolidenyl carbene catalyzes nucleophilic acylation reaction of arylfluorides with electron withdrawing groups to give benzophenone derivatives.

Cited by 69 publications

References 11 publications

Synthesis of Heterocyclic Compounds via Nucleophilic Aroylation Catalyzed by Imidazolidenyl Carbene

Synthesis of Heterocyclic Compounds via Nucleophilic Aroylation Catalyzed by Imidazolidenyl Carbene

Nucleophilic Aroylation on Fluoroquinazolines Catalyzed by N-Heterocyclic Carbenes

Cyano-Phosphorylation of Aldehydes Catalyzed by a Nucleophilic N-Heterocyclic Carbene

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