- Copper-catalyzed cascade radical cyclization of alkynoates: Construction of aryldifluoromethylated coumarins
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A mild and simple method is reported for the construction of 3-difluoroarylmethylated coumarins using α,α-difluoroarylacetic acids as an easily handled difluoromethyl source in reaction with ester 3-arylpropiolates under the promotion of copper. The reaction involves a proposed radical-triggered domino decarboxylative aryldifluoromethylation/5-exo cyclization/ester migration process that directly forms Csp2-CF2Ar and C-C bonds with good functional group tolerance. This journal is
- Chen, Zhiwei,Huang, Xiaoxiao,Tang, Wei,Zeng, Piaopiao
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supporting information
p. 10223 - 10227
(2021/12/10)
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- Generation of Axially Chiral Fluoroallenes through a Copper-Catalyzed Enantioselective β-Fluoride Elimination
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Herein we report the copper-catalyzed silylation of propargylic difluorides to generate axially chiral, tetrasubstituted monofluoroallenes in both good yields (27 examples >80%) and enantioselectivities (82-98% ee). Compared to previously reported synthetic routes to axially chiral allenes (ACAs) from prochiral substrates, a mechanistically distinct reaction has been developed: the enantiodiscrimination between enantiotopic fluorides to set an axial stereocenter. DFT calculations and vibrational circular dichroism (VCD) suggest that β-fluoride elimination from an alkenyl copper intermediate likely proceeds through a syn-β-fluoride elimination pathway rather than an anti-elimination pathway. The effects of the C1-symmetric Josiphos-derived ligand on reactivity and enantioselectivity were investigated. Not only does this report showcase that alkenyl copper species (like their alkyl counterparts) can undergo β-fluoride elimination, but this elimination can be achieved in an enantioselective fashion.
- Liu, Peng,Mai, Binh Khanh,Nafie, Jordan,O'Connor, Thomas J.,Toste, F. Dean
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supporting information
p. 13759 - 13768
(2021/09/07)
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- Fe(III)-Catalyzed Decarboxylative C3-Difluoroarylmethylation of Coumarins with α,α-Difluoroarylacetic Acids
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A facile Fe(III)-catalyzed oxidative decarboxylative radical coupling reaction of α,α-difluoroarylacetic acids with coumarins has been developed. This transformation, which provides a series of C-3 difluoroarylmethylated coumarins containing various functional groups in moderate-to-good yields, features easily accessible starting materials and operational simplicity.
- Chen, Zhiwei,Bai, Xiang,Sun, Jie,Xu, Yicheng
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supporting information
p. 7674 - 7682
(2020/07/15)
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- Controlling the cleavage of carbon-carbon bonds to generate α,α-difluorobenzyl carbanions for the construction of difluoromethylbenzenes
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Controlling the cleavage of carbon-carbon bonds during a chemical reaction is a substantial challenge; however, synthetic methods that accomplish this objective produce valuable and often unexplored reactivity. We have designed a mild process to generate α,α-difluorobenzyl carbanions in the presence of potassium carbonate by exploiting the cleavage of C-C bonds during the release of trifluoroacetate. The initiating reagent is potassium carbonate, which represents an improvement over existing protocols that require a strong base. Fragmentation studies across substituted arenes and heteroarenes were conducted along with computational analyses to elucidate reactivity trends. Furthermore, the mildly generated α,α-difluorobenzyl carbanions from electron-deficient aromatics and heteroaromatic rings can react with aldehydes to create derivatives of difluoromethylbenzenes, which are valuable synthetic targets.
- Khatri, Hari R.,Han, Changho,Luong, Erica,Pan, Xiaoliang,Adam, Amna T.,Alshammari, Maali D.,Shao, Yihan,Colby, David A.
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p. 11665 - 11675
(2019/10/02)
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- Silver-Catalyzed Decarboxylative Alkynylation of α,α-Difluoroarylacetic Acids with Ethynylbenziodoxolone Reagents
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A decarboxylating alkynylation of α,α-difluoroarylacetic acids with ethynylbenziodoxolone reagents is reported. AgNO3 serves as the catalyst and K2S2O8 as the oxidant. A series of functional groups were tolerated, and moderate to good yields were obtained.
- Chen, Fei,Hashmi, A. Stephen K.
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supporting information
p. 2880 - 2882
(2016/07/06)
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- Easy Access to Difluoromethylene-Containing Arene Analogues through Palladium-Catalysed C–H Olefination
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An efficient palladium-catalysed ortho-C–H olefination of α,α-difluorophenylacetic acid derivatives using 8-aminoquinoline as a bidentate directing group has been developed. A range of olefinated arenes can thus be synthesized in a concise way. This reaction provides an easy and straightforward route to a panel of difluoromethylated arene analogues in moderate to good yields, with a satisfactory tolerance of common functional groups. Transformation of the products into a variety of other difluoromethylene-containing compounds demonstrates the utility of this method.
- Shao, Changdong,Shi, Guangfa,Zhang, Yanghui
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supporting information
p. 5529 - 5538
(2016/11/25)
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- Method of manufacturing arom. defluoromethyl compd.
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PROBLEM TO BE SOLVED: To provide a method for easily producing an aromatic compound having a difluoromethyl group in high yield while using a reagent having low toxicity. SOLUTION: The method for producing the aromatic difluoromethyl compound includes reacting an aromatic difluoroacetic acid in the presence of a metal halide (especially potassium fluoride). COPYRIGHT: (C)2011,JPOandINPIT
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Paragraph 0075
(2018/11/22)
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- Pd-catalyzed α-arylation of trimethylsilyl enolates of α,α-difluoroacetamides
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We report the arylation and heteroarylation of α,α-difluoro-α-(trimethylsilyl)acetamides with aryl and heteroaryl bromides catalyzed by an air- and moisture-stable palladacyclic complex containing P(t-Bu)2Cy as ligand. A broad range of electronically varied aryl and heteroaryl bromides underwent this transformation to afford α-aryl-α,α-difluoroacetamides in high yields. Due to the electrophilicity of the fluorinated amide, this palladium-catalyzed cross-coupling reaction provides a versatile platform to generate a range of α,α-difluoro carbonyl compounds, such as α-aryl-α,α-difluoroketones, -acetaldehydes, -acetates, and acetic acids, and difluoroalkyl derivatives, such as 2-aryl-2,2-difluoroethanols and -ethylamines, under mild conditions.
- Ge, Shaozhong,Arlow, Sophie I.,Mormino, Michael G.,Hartwig, John F.
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supporting information
p. 14401 - 14404
(2014/12/11)
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- Catalytic decarboxylative fluorination for the synthesis of Tri- and difluoromethyl arenes
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Treatment of readily available α,α-difluoro- and α-fluoroarylacetic acids with Selectfluor under Ag(I) catalysis led to decarboxylative fluorination. This operationally simple reaction gave access to tri- and difluoromethylarenes applying a late-stage fluorination strategy. Translation to [18F]labeling is demonstrated using [ 18F]Selectfluor bis(triflate), a reagent affording [ 18F]tri- and [18F]difluoromethylarenes not within reach with [18F]F2.
- Mizuta, Satoshi,Stenhagen, Ida S.R.,O'Duill, Miriam,Wolstenhulme, Jamie,Kirjavainen, Anna K.,Forsback, Sarita J.,Tredwell, Matthew,Sandford, Graham,Moore, Peter R.,Huiban, Mickael,Luthra, Sajinder K.,Passchier, Jan,Solin, Olof,Gouverneur, Véronique
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supporting information
p. 2648 - 2651
(2013/07/11)
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- METHOD FOR PRODUCING AROMATIC DIFLUOROACETIC ACID ESTER
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Disclosed is a method for producing a compound having a difluoromethylene group at an even lower cost and with excellent yield. The production method of the present invention is a method for producing an aromatic difluoroacetic acid ester, which comprises reacting an iodobenzene containing an electro attracting group and an α-silyl difluoroacetic acid ester in the presence of a metal halide.
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Page/Page column 7-8
(2012/09/10)
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