- Glycosyl Cross-Coupling with Diaryliodonium Salts: Access to Aryl C -Glycosides of Biomedical Relevance
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A stereospecific cross-coupling reaction of anomeric nucleophiles with diaryliodonium triflates resulting in the synthesis of aryl C-glycosides is reported. This process capitalizes on a stereoretentive reaction of configurationally stable C1 stannanes and is promoted by a palladium catalyst in the presence of a bulky phosphine ligand that suppresses the undesired β-elimination. The utility of this reaction has been demonstrated in the preparation of a series of C-glycosides derived from common saccharides resulting in exclusive transfer of anomeric configuration from the anomeric nucleophile to the product, and in the synthesis of empagliflozin, a commercial antidiabetic drug.
- Yi, Duk,Zhu, Feng,Walczak, Maciej A.
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supporting information
p. 1936 - 1940
(2018/04/12)
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- Visible-Light Photoredox Difluoromethylation of Phenols and Thiophenols with Commercially Available Difluorobromoacetic Acid
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A simple and efficient visible-light photoredox one-pot method for difluoromethylation of phenols and thiophenols has been developed. The protocol uses commercially available, inexpensive, and easy handling difluorobromoacetic acid as the difluoromethylating agent, and the diverse O- and S-difluoromethylated products were prepared in good yields with tolerance of many functional groups.
- Yang, Jinyan,Jiang, Min,Jin, Yunhe,Yang, Haijun,Fu, Hua
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supporting information
p. 2758 - 2761
(2017/05/24)
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- Decarboxylative Trifluoromethylating Reagent [Cu(O2CCF3)(phen)] and Difluorocarbene Precursor [Cu(phen)2][O2CCF2Cl]
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This article describes the new economic decarboxylative trifluoromethylating reagent [Cu(phen)(O2CCF3)] (1; phen=1,10-phenanthroline) and the efficient difluorocarbene precursor [Cu(phen)2][O2CCF2Cl] (2). Treatment of copper tert-butoxide with phen and subsequent addition of trifluoroacetic acid or chlorodifluoroacetic acid afforded air-stable complexes 1 and 2, respectively, which were characterized by X-ray crystallography. The copper(I) ion in 1 is coordinated by a bidentate phen ligand, a monodentate trifluoroacetate group, and a molecule of CH3CN in a distorted tetrahedral coordination geometry. The molecular structure of 2 adopts an ionic form that consists of a [Cu(phen)2]+ cation and a chlorodifluoroacetate anion. Complex 1 reacted with a variety of aryl and heteroaryl halides to form trifluoromethyl (hetero)arenes in good yields. The corresponding Hammett plot exhibited a linear relationship and a reaction parameter (ρ)=+0.56±0.02, which indicated that the trifluoromethylation reaction proceeded via a nucleophilic reactive species. Complex 2 reacts with phenols to produce aryl difluoromethyl ethers in modest-to-excellent yields. Mechanistic investigations revealed that the difluoromethylation reaction proceeds by initial copper-mediated formation of difluorocarbene and subsequent concerted addition of difluorocarbene to the phenol to form a three-center transition state.
- Lin, Xiaoxi,Hou, Chuanqi,Li, Haohong,Weng, Zhiqiang
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supporting information
p. 2075 - 2084
(2016/02/12)
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- OXIME DERIVATIVE, METHOD OF PRODUCING THE SAME AND INSECTICIDE COMPRISING THE SAME AS ACTIVE INGREDIENT
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PROBLEM TO BE SOLVED: To provide a compound having excellent insecticidal effect and useful as an active ingredient of an insecticide. SOLUTION: This invention provides an oxime derivative represented by general formula (1) (where Ra, X and n represent definitions described in the specifications) and an insecticide that comprises the same as an active ingredient. COPYRIGHT: (C)2015,JPOandINPIT
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Paragraph 0187-0189
(2018/10/03)
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- SYNTHESIS OF DIFLUOROMETHYL ETHERS AND SULFIDES
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The synthesis of difluoromethyl ethers and sulfides with a simple, non-ozone- depleting reagent is described. The difluoromethylation of phenols with this reagent occurs at room temperature within minutes with exceptional functional group tolerance. The mild conditions makes possible tandem processes for the conversion of aryl boronic acids, aryl halides and arenes to difluoromethyl ethers. Mechanistic studies support a reaction pathway involving nucleophilic attack of the phenolate to difluorocarbene.
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Paragraph 0078-0082; 0095-0098
(2014/07/22)
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- Chlorodifluoromethyl aryl ketones and sulfones as difluorocarbene reagents: The substituent effect
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We have investigated the different chlorodifluoromethyl aryl ketones 1a-1g and sulfones 2a-2h as difluorocarbene reagents for O- and N- difluoromethylations. It was found that the sulfone reagents 2 were generally more efficient in difluoromethylation than the ketone reagents 1. Furthermore, while the different substituents on ketone reagents 1 did not show a remarkable impact on the difluoromethylation reaction, the substituent effect on the sulfone reagents 2 was much more significant. Finally, we found that p-chlorophenyl chlorodifluoromethyl sulfone 2d and p-nitrophenyl chlorodifluoromethyl sulfone 2h were among the most powerful difluorocarbene reagents in this category for O-difluoromethylations.
- Wang, Fei,Zhang, Laijun,Zheng, Ji,Hu, Jinbo
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experimental part
p. 521 - 528
(2011/08/22)
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- Chlorodifluoromethyl phenyl sulfone: A novel non-ozone-depleting substance-based difluorocarbene reagent for O- and N-difluoromethylations
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Chlorodifluoromethyl phenyl sulfone, a previously unknown compound that can be readily prepared from non-ODS-based precursors, was found to act as a robust difluorocarbene reagent for O- and N-difluoromethylations. The Royal Society of Chemistry.
- Zheng, Ji,Li, Ya,Zhang, Laijun,Hu, Jinbo,Meuzelaar, Gerrit Joost,Federsel, Hans-Juergen
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p. 5149 - 5151
(2008/09/18)
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- 2-Chloro-2,2-difluoroacetophenone: A non-ODS-based difluorocarbene precursor and its use in the difluoromethylation of phenol derivatives
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A novel and non-ODS-based (ODS = ozone-depleting substance) preparation of 2-chloro-2,2-difluoroacetophenone (1) was achieved in high yield by using 2,2,2-trifluoroacetophenone as the starting material. Compound 1 was found to act as a good difluorocarbene reagent, which readily reacts with a variety of structurally diverse phenol derivatives 4 in the presence of potassium hydroxide or potassium carbonate to produce aryl difluoromethyl ethers 5 in good yields. This new and easy-to-handle synthetic methodology offers an environmentally friendly alternative to other Freon- or Halon-based difluoromethylating approaches.
- Zhang, Laijun,Zheng, Ji,Hu, Jinbo
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p. 9845 - 9848
(2007/10/03)
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- SYNTHESIS AND REACTIONS OF DIFLUOROMETHOXY- AND DIFLUOROCHLOROMETHOXY DERIVATIVES OF BENZENE
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Difluoromethoxybenzaldehydes were synthesized by difluoromethylation of aromatic o- and p-hydroxyaldehydes by chladone-22 in alkaline medium.Chlorination of the difluoromethoxybenzene derivatives under illumination gave difluorochloromethoxy benzene with various function groups (F, Cl, CN, COCl, COOH).The values of the ?-constants of the OCF2Cl group have been determined.In its electronic characteristics it is similar to the OCF3 group.
- Shelyazhenko, S. V.,Fialkov, Yu. A.,Yagupol'skii, L. M.
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p. 1317 - 1324
(2007/10/02)
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