- Nickel-Catalyzed Decarbonyloxidation of 3-Aryl Benzofuran-2(3H)-ones to 2-Hydroxybenzophenones
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We have developed a protocol to facilitate the nickel-catalyzed decarbonyloxidation of 3-aryl benzofuran-2(3H)-ones to 2-hydroxybenzophenones under mild conditions, which is an efficient approach for the decarbonyloxidation of lactones in organic synthesis. A diverse range of substrates can undergo C(O)-O/C(O)-C bond cleavage to generate the target products in good yields. These 2-hydroxybenzophenones can be converted into a variety of compounds via reactions such as esterification, cyclization, and reduction.
- Tong, Zhou,Tang, Zhi,Au, Chak-Tong,Qiu, Renhua
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p. 8533 - 8543
(2020/07/16)
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- Ring-closure reaction of 2-benzoylbenzenediazonium salts in 1-butyl-3- methylimidazolium ionic liquids
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A ring-closure reaction by thermal dediazoniation of 2-substituted benzenediazonium tetrafluoroborates in imidazolium-based ionic liquids was investigated. Dediazoniation of 2-(4-R-benzoyl)benzenediazonium tetrafluoroborates (R = H, Me, OMe, Cl) in ionic liquid [BMIM][TfO] gave 3-R-9-fluorenones as ring-closure products and 2-(4-R-benzoyl)phenyl trifluoromethanesulfonates as substitution products. Dediazoniation in [BMIM][Tf2N] afforded 3-R-9-fluorenones and R-C6H4-CO-C6H4-OSO(CF3)(NSO2CF3). Yields of the ring-closure products were higher in [BMIM][Tf2N] than in [BMIM][TfO]. 2-Benzylbenzenediazonium and 2-phenoxybenzenediazonium tetrafluoroborates exclusively produced substitution products in both ionic liquids. DFT calculations suggest that electron transfer from the anion to render homolytic process should be induced more readily in [BMIM][Tf2N] than in [BMIM][TfO]. This ability may be responsible for the higher yields of the ring-closure products via homolytic pathway and the smaller yields of the substitution products via heterolytic pathway in [BMIM][Tf2N].
- Okazaki, Takao,Yamamoto, Hiroyuki,Kitagawa, Toshikazu
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- Synthesis of isoindole derivatives by palladium-catalyzed domino reaction of (2-alkynyl)phenylketone o-pentafluorobenzoyloximes
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Isoindole derivatives were synthesized by the palladium-catalyzed cyclization of (2-alkynyl)phenylketone O-pentafluoro-benzoyloximes in the presence of organometallic compounds such as sodium formate and aryl boronic acid. Georg Thieme Verlag Stuttgart - New York.
- Kitamura, Mitsuru,Moriyasu, Yohei,Okauchi, Tatsuo
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experimental part
p. 643 - 646
(2011/05/02)
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- Photogeneration and chemistry of biphenyl quinone methides from hydroxybiphenyl methanols
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The photosolvolysis of several biphenyl methanols (Ph-PhCH[Ph]OH) substituted with hydroxy or methoxy groups on the benzene ring not containing the -CH(Ph)OH moiety has been studied in aqueous solution. This work is a continuation of our studies of photosolvolysis of hydroxy-substituted arylmethanols that generate quinone methide intermediates, some of which are known to be relevant intermediates in toxicology and in biological and organic chemistry in general. In this study, we further probe the ability of the biphenyl ring system to transmit charge from the ring substituted with a potential electron-donating group (hydroxy and methoxy) to the adjacent benzene ring that contains a labile benzyl alcohol moiety. We show that in systems with a hydroxy substituent, biphenyl quinone methides (BQM) are the first formed intermediates that are detectable by nanosecond laser flash photolysis, and are responsible for the observed overall photosolvolysis reaction of these compounds. The highly conjugated BQM are found to absorb at long wavelengths (λmax 580 and ~750 nm for the p,p′ and o,p′-isomers, respectively) with relatively long lifetimes in neutral aqueous solution (500 and 30 μs, respectively). The BQM from the o,p′-isomer was found to undergo a competing intramolecular Friedel-Crafts alkylation, to give a fluorene derivative.
- Xu, Musheng,Lukeman, Matthew,Wan, Peter
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- Iron-catalyzed aryl-aryl cross-couplings with magnesium-derived copper reagents
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(Chemical Equation Presented) Well-matched couples: Functionalized aryl and heteroaryl copper species obtained from the corresponding magnesium derivatives undergo Fe-catalyzed cross-coupling reactions with aryl iodides that bear keto, ester, triflate, or nitrile groups (see scheme).
- Sapountzis, Ioannis,Lin, Wenwei,Kofink, Christiane C.,Despotopoulou, Christina,Knochel, Paul
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p. 1654 - 1657
(2007/10/03)
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