Copper-Catalyzed Cyclization of<i>N</i>-Allylhalodifluoroacetamides:  An Efficient Synthesis of α,α-Difluorinated γ-Lactams

Nagashima, Hideo; Isono, Yoshimi; Iwamatsu, Sho‐ichi

doi:10.1021/jo001187f

Cited by 84 publications

(31 citation statements)

References 24 publications

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“…Nagashima et al have demonstrated that an amide substrate bearing a bromodifluoromethyl group has two rotamers; one is suitable for the reaction and the other is not. [13] According to their work, substrate 6 should exist as two rotamers with an equal distribution of regioisomers. When treated under the optimized reaction conditions, substrate 6 delivered only the product 3h, in 49 % yield [Equation (3)].…”

Section: Resultsmentioning

confidence: 99%

“…19 F NMR spectra were taken with a Bruker AM 300 (282 MHz) spectrometer and PhCF 3 as external standard. 13 C NMR spectra were taken a Bruker AM 400 (100 MHz) spectrometer. IR spectra were obtained with a Nicolet AV-360 spectrophotometer.…”

Section: Methodsmentioning

confidence: 99%

“…1 H NMR (400 MHz, CDCl 3 ): δ = 8.13 (s, 1 H), 7.65 (d,J = 7.4 Hz,1 H),2 H),7.32 (t,J = 7.3 Hz, 1 H), 7.20 (t, J = 7.3 Hz, 2 H), 6.98-6.93 (m, 3 H), 3.63 (q, J = 9.7 Hz, 2 H), 3.14 (s, 3 H) ppm. 13 C NMR (100 MHz, CDCl 3 ): δ = 167.20 (d,J = 2.3 Hz),155.84,148.94 (t,J = 25.7 Hz),147.18,130.05,128.33,127.30,123.70,123.67,122.80,121.93,121.64,119.67 N-Benzyl-2-bromo-2,2-difluoro-N-(4-hydroxybenzyl) 13 C NMR (100 MHz, CDCl 3 ): δ = 160.25 (td, J = 26. 5,8.1 Hz),156.20,156.01,135.04,134.35,129.86,129.06,129.01,128.95,128.27,128.14,128.05,127.30,126.59,125.64,116.02,115.91,110.90 (t,J = 314.7 Hz),50.35,50.18,48.41 ppm.…”

Section: Dearomatization Of Phenolsmentioning

confidence: 99%

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Rhodium‐Catalyzed Intramolecular Difluoromethylenative Dearomatization of Phenols

Zhang

et al. 2013

Eur J Org Chem

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Rhodium‐catalyzed intramolecular difluoromethylenative dearomatization of phenols to yield azaspirocyclohexadienones containing all‐carbon quaternary centers in good to excellent yields was developed. A variety of functional groups proved compatible with the transformation. This method could also be used for difluoromethylenative dearomatization of indoles. Preliminary mechanism studies suggest that a pure radical mechanism is not involved in this reaction.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Dearomatization Of Phenolsmentioning

confidence: 99%

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Rhodium‐Catalyzed Intramolecular Difluoromethylenative Dearomatization of Phenols

Zhang

et al. 2013

Eur J Org Chem

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“…The Nagashima research group applied its efficient ATRC strategy to various N ‐allyl ‐N ‐tosylhalodifluoroacetamides . They established the role of the N ‐tosyl group was to lower the rotational barriers of the fluorinated amides leading to facile access of the rotamer favorable for the cyclization, namely that arranging CF 2 ‐X and allyl group in the s‐cis configuration (Scheme ).…”

Section: Intramolecular α‐Alkylation Of α‐Haloamides: Syntheses Of γ‐mentioning

confidence: 99%

The Fascinating Chemistry of α‐Haloamides

et al. 2020

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The aim of this review is to highlight the rich chemistry of α‐haloamides originally mainly used to discover new C−N, C−O and C−S bond forming reactions, and later widely employed in C−C cross‐coupling reactions with C(sp3), C(sp2) and C(sp) coupling partners. Radical‐mediated transformations of α‐haloamides bearing a suitable located unsaturated bond has proven to be a straightforward alternative to access diverse cyclic compounds by means of either radical initiators, transition metal redox catalysis or visible light photoredox catalysis. On the other hand, cycloadditions with α‐halohydroxamate‐based azaoxyallyl cations have garnered significant attention. Moreover, in view of the important role in life and materials science of difluoroalkylated compounds, a wide range of catalysts has been developed for the efficient incorporation of difluoroacetamido moieties into activated as well as unactivated substrates.

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“…21,22 For example in 2010, copper-mediated cross-coupling with difluoroiodoacetamides was demonstrated by Hu and coworkers. 21 When we attempted trifluoroacetate release/iodination with 1 , the combination of LiI/Selectfluor/Et 3 N did not provide a high conversion to the α,α-difluoro-α-iodomethyl ketone as expected.…”

mentioning

confidence: 99%

Synthesis of α-Halo-α,α-difluoromethyl Ketones by a Trifluoroacetate Release/Halogenation Protocol

John

Colby

2011

J. Org. Chem.

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Three series of α-halo-α,α-difluoromethyl ketones are prepared from highly α-fluorinated gem-diols by exploiting the facile release of trifluoroacetate, followed by immediate trapping of the liberated α,α-difluoroenolate with an electrophilic chlorine, bromine, or iodine source. The products are typically isolated in good yields, even in the case of sensitive, α-iodo-α,α-difluoromethyl ketones. Also, we demonstrate that an α-iodo-α,α-difluoromethyl ketone will participate in a copper-promoted reaction to forge a new carbon–carbon bond.

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Copper-Catalyzed Cyclization ofN-Allylhalodifluoroacetamides: An Efficient Synthesis of α,α-Difluorinated γ-Lactams

Cited by 84 publications

References 24 publications

Rhodium‐Catalyzed Intramolecular Difluoromethylenative Dearomatization of Phenols

Rhodium‐Catalyzed Intramolecular Difluoromethylenative Dearomatization of Phenols

The Fascinating Chemistry of α‐Haloamides

Synthesis of α-Halo-α,α-difluoromethyl Ketones by a Trifluoroacetate Release/Halogenation Protocol

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