- Electrochemical [4+2] Annulation-Rearrangement-Aromatization of Styrenes: Synthesis of Naphthalene Derivatives
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We report the first electrochemical strategy to synthesize functionalized naphthalene derivatives through [4+2] annulation—rearrangement–aromatization from styrenes under mild conditions. The electrolysis does not require metals, oxidants and high valence substrates, indicating the atom and step-economy ideals. The dehydrodimer produced through [4+2] cycloaddition of 4-methoxy α-methyl styrene is isolated and proved to be the key intermediate for the following oxydehydrogenation to form carbon cation, which undergoes rearrangement–aromatization to afford the final products. This reaction represents a powerful access to construct multi-substituted naphthalene blocks in a single step.
- Ma, Yueyue,Lv, Jufeng,Liu, Chengyu,Yao, Xiantong,Yan, Guoming,Yu, Wei,Ye, Jinxing
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supporting information
p. 6756 - 6760
(2019/04/17)
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- One-Pot Photomediated Giese Reaction/Friedel-Crafts Hydroxyalkylation/Oxidative Aromatization to Access Naphthalene Derivatives from Toluenes and Enones
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Value-added chemicals, γ-aryl ketones and naphthalenes, were conveniently synthesized from readily available toluenes and enones through the synergistic combination of photoredox and Lewis acid catalysis. The direct synthesis of γ-aryl ketones represents a rare example of Giese reactions between benzylic C(sp3)-H and enones that avoids the use of prefunctionalized metallic nucleophiles. Naphthalene derivatives were accessed through a one-pot Giese reaction/Friedel-Crafts hydroxyalkylation/oxidative aromatization sequential transformation.
- Liu, Haiwang,Ma, Lishuang,Zhou, Rong,Chen, Xuebo,Fang, Weihai,Wu, Jie
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p. 6224 - 6229
(2018/06/11)
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- Generation of VBr? VBi? VO?? defect clusters for 1O2 production for molecular oxygen activation in photocatalysis
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Defect engineering on a semiconductor surface can provide coordinatively unsaturated sites for molecular oxygen activation in photocatalysis. In this work, we demonstrated that the vacancy type was key to modulate the molecular oxygen activation process on BiOBr nanosheets. By regulating the reaction time, an oxygen vacancy (VO??), a double atom defect cluster (VBi? VO??) and triple atom clusters (VBi? VO?? VBi? and VBr? VBi? VO??) were accordingly generated on the surface, subsurface and bulk of BiOBr. More importantly, the newly-discovered VBr? VBi? VO?? defect cluster was highly related to the singlet oxygen (1O2) production ability of BiOBr. Meanwhile, the excellent photocatalytic selective oxidation reactions were successfully realized over BiOBr with the VBr? VBi? VO?? defect cluster. In addition, time-dependent defect cluster generation and the associated molecular oxygen activation were discussed.
- Ding, Jie,Dai, Zan,Tian, Fan,Zhou, Bo,Zhao, Bin,Zhao, Huiping,Chen, Zhiquan,Liu, Yunling,Chen, Rong
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supporting information
p. 23453 - 23459
(2017/11/30)
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- New singlet oxygen donors based on naphthalenes: Synthesis, physical chemical data, and improved stability
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Singlet oxygen donors are of current interest for medical applications, but suffer from a short half-life leading to low singlet oxygen yields and problems with storage. We have synthesized more than 25 new singlet oxygen donors based on differently substituted naphthalenes in only a few steps. The influence of functional groups on the reaction rate of the photooxygenations, thermolysis, half-life, and singlet oxygen yield has been thoroughly studied. We determined various thermodynamic data and compared them with density functional calculations. Interestingly, remarkable stabilities of functional groups during the photooxygenations and stabilizing effects for some endoperoxides during the thermolysis have been found. Furthermore, we give evidence for a partly concerted and partly stepwise thermolysis mechanism leading to singlet and triplet oxygen, respectively. Our results might be interesting for "dark oxygenations" and future applications in medicine.
- Klaper, Matthias,Linker, Torsten
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p. 8569 - 8577
(2015/06/02)
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- MISE EN EVIDENCE DE LA DEPROTONATION DU COMPLEXE IPSO-ARENIUM OBTENU EN PHENYLATION CATIONIQUE DU DIMETHYL-1,4 NAPHTALENE
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The phenyl cations obtained from the thermolysis of benzenediazonium tetrafluoroborate react with 1,4-dimethylnaphthalene in DMSO to give 1-methyl 4-methylene 1-phenyl 1,4-dihydronaphthalene as well as the phenylation products at positions 2,5 and 6.The formation of the former provides direct evidence for the attack of C6H5+ ipso to the methyl group.Either in pure 1,4-dimethylnaphthalene or in acetonitrile solution, the deprotonation of the ipso-arenium ions has not been observed and the main reaction was the 1-2 migration of the phenyl group.The reactivity of the ipso position in regard to attack by phenyl cations and the reactivity of the 2 position are very similar. 1-methyl 4-phenyl naphthalene has not been detected by G L C so that demethylphenylation of 1,4-dimethylnaphthalene must be negligible.
- Court, J.,Ioakimoglou, H.,Lambeaux, C.,Bonnier, J. M.
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p. 5601 - 5606
(2007/10/02)
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