- Electrochemical oxidative decarboxylation and 1,2-aryl migration towards the synthesis of 1,2-diaryl ethers
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Carboxylic acid compounds are important chemicals and are widely present in various natural products. They are not only nucleophiles, but also radical precursors. Classic transition-metal-catalyzed and photochemical decarboxylation have shown their excellent site selectivity in radical chemistry. However, electrochemical decarboxylation with a long history hasn't got enough attention in recent years. In this work, the electrochemical oxidative decarboxylation and 1,2-aryl migration of 3,3-diarylpropionic acids have been introduced to construct C-O bonds with alcohols. Remarkably, this transformation can proceed smoothly without metal catalysts and external oxidants.
- Bu, Faxiang,Hu, Xia,Lei, Aiwen,Lu, Lijun,Wang, Shengchun,Zhang, Heng
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p. 10000 - 10004
(2020/10/06)
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- Oxyarylation and aminoarylation of styrenes using photoredox catalysis
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A three-component coupling of styrenes is reported, using photoredox catalysis to achieve simultaneous arylation and C-O or C-N bond formation across the styrene double bond.
- Fumagalli, Gabriele,Boyd, Scott,Greaney, Michael F.
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supporting information
p. 4398 - 4401
(2013/09/24)
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- Gold-catalysed oxyarylation of styrenes and mono- and gem-disubstituted olefins facilitated by an iodine(III) oxidant
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1-Hydroxy-1,2-benziodoxol-3(1H)-one (IBA) is an efficient terminal oxidant for gold-catalysed, three-component oxyarylation reactions. The use of this iodine(III) reagent expands the scope of oxyarylation to include styrenes and gem-disubstituted olefins, substrates that are incompatible with the previously reported Selectfluor-based methodology. Diverse arylsilane coupling partners can be employed, and in benzotrifluoride, homocoupling is substantially reduced. In addition, the IBA-derived co-products can be recovered and recycled. The I's have it: The unprecedented use of an iodine(III) reagent as the terminal oxidant for gold-catalysed oxyarylation allows the substrate scope to be significantly expanded; in addition to monosubstituted olefins, styrenes and gem-disubstituted olefins are well tolerated (see scheme). With benzotrifluoride as solvent, unproductive homodimerisation of the arylsilane coupling partner is effectively suppressed. Copyright
- Ball, Liam T.,Lloyd-Jones, Guy C.,Russell, Christopher A.
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experimental part
p. 2931 - 2937
(2012/04/23)
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- α-Methoxy-benzylmetals: Original synthesis and reactivity
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Although 1-methoxy-1-methylseleno-toluene is efficiently metallated by KDA, the same compound as well as its higher homologues react with t-butyllithium producing 1-methoxy benzyllithiums via the C-Se bond cleavage. These species are efficiently alkylated by alkyl halides, even the secondary ones and react with THF in the presence of BF3-OEt2 to produce the homologated tetrahydropyran derivative in good yield.
- Krief, Alain,Bousbaa, Jamal
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p. 6289 - 6290
(2007/10/03)
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- GAS-SOLID REACTIONS IN ORGANIC SYNTHESIS
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Various new branches in the field of preparative scale organic gas-solid reactions (additions, substitutions, eliminations, condensations) are elaborated following a historical review.Polar gases (HBr, HCl, HI, HSCH3) react at 1 bar and temperatures from 40 to -80 degC with gram quantities of crystalline N-vinylimides, -amides, -amines, and S-vinylthioethers usually in the Markovnikov orientation, but there is also an exception.The polar gases H2O and NH3 transform some of the crystalline addition products and H2O may be added catalytically to N-vinylphthalimide.All reactions run to high conversion rapidly and several of the highly sensitive products cannot be synthesized in soluton.Liquid compounds like N-vinylpyrrolidinone which polymerize in solution crystallize and add polar gases smoothly upon freezing.Polar gases are applied to crystalline chalcone, cinnamic acid, and stilbenes with variable success.Pd-doped crystals are hydrogenated.Contrary to literature reports chlorine and bromine add to crystalline stilbene non-stereospecifically and without significant substitution.The results are discussed with respect to X-ray structures and powder diffraction patterns.Educt and product crystals are not isotypical.Various solid state decompositions are uncovered and the synthetic value is stressed.
- Kaup, Gerd,Matthies, Doris
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p. 119 - 143
(2007/10/02)
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- Organic Gas-Solid Reactions with Stilbenes, Chalcones, and Enamides
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Crystalline stilbene (1) adds gaseous chlorine and bromine without intermediate melting.The stereoselectivity is similar to that observed in solutions.Triphenylethene (3) also yields the products 4 in gas-solid reactions with chlorine and bromine, but these products tend to loose HX from the crystal; their conversion products are described.Neither crystalline 1 nor 3, but (E)-1,2-diphenyl-1-propene (7) adds gaseous hydrogen bromide regiospecifically.The same is true for the crystalline chalcone 10, which adds hydrogen bromide and -chloride selectively to give 11 nonisotypically.Gaseous ammonia reconverts crystalline 11 into 10.The enamide 12 in its crystalline state adds the gases hydrogen bromide, -chloride, methanethiol and hydrogen, to give the products 13, but also 15 (addition and condensation) and 16 (double addition). 13f which is formed via hydrogenation of crystals is not isotypical with its precursor 12.The liquid 17 crstallizes on freezing and then easily adds the gases hydrogen bromide (> - 50 deg C) and hydrogen chloride (> - 80 deg C) in highly controlled reactions to give the reactive compounds 18.These are converted not only into oligomers but also into the derivatives 19, 20, 21, and 22.The advantages of the unusual reaction procedures are discussed.
- Kaupp, Gerd,Matthies, Doris
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p. 1897 - 1904
(2007/10/02)
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