Birch‐Type Photoreduction of Arenes and Heteroarenes by Sensitized Electron Transfer
作者:Anamitra Chatterjee、Burkhard König
DOI:10.1002/anie.201905485
日期:2019.10
energy-transfer and electron-transfer processes generates an arene radical anion, which is subsequently trapped by hydrogen-atom transfer and finally protonated to form the dearomatized product. The photoreduction converts planar aromatic feedstock compounds into molecular skeletons that are of use in organic synthesis.
Palladium‐Catalyzed Dearomative
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‐1,4‐Carboamination with Grignard Reagents
作者:Conghui Tang、Mikiko Okumura、Yunbo Zhu、Annie R. Hooper、Yu Zhou、Yu‐Hsuan Lee、David Sarlah
DOI:10.1002/anie.201905021
日期:2019.7.22
functionalization of simple, nonactivated arenes with Grignardreagents has been established. This one‐pot method features a visible‐light‐mediated [4+2] cycloaddition between an arene and an arenophile, and subsequent palladium‐catalyzed allylic substitution of the resulting cycloadduct with a Grignardreagent. A variety of arenes and Grignardreagents can participate in this process, forming carboaminated
Photochemistry of 1-phenyl-1,2-dihydronaphthalene in methanol
作者:Jan Woning、Frank A. T. Lijten、Wim H. Laarhoven
DOI:10.1021/jo00007a033
日期:1991.3
The photochemistry of 1-phenyl-1,2-dihydronaphthalene (1) in methanol and hexane has been investigated. The lack of influence of solvent polarity and of the presence of sulfuric acid on the rate of formation of exo-4-phenylbenzobicyclo[3.1.0]hex-2-ene (exo-2) from the primary, ring-opened photoproduct cZt-3a of 1 precludes a sudden-polarized, zwitterionic excited state from being involved in the intramolecular [4 + 2] photocycloaddition reaction leading to exo-2. The experimental results can be rationalized by assuming that this photoprocess involves a concerted pi-4a + pi-2a-type electrocyclic reaction. cis-Dibenzobicyclo[3.3.0]octa-2,7-diene (8) is proposed to arise by photocyclization of cZc-3b, followed by a thermal rearrangement. On irradiation of 1 with a broad-spectrum lamp, the ratio of the photoproducts exo-2 and 8 is correlated with the ratio of the pe and pa conformers of 1. The novel compound 1-(o-benzylphenyl)allene (6) is also formed under these conditions. Irradiation of 1 at 254 nm yields 8 as the only photoproduct. Photochemical addition of methanol was observed to complete with the photoprocess, leading to exo-2, though at a comparatively low level. A photodecomposition mode of exo-2, presumably involving heterolytic cleavage of the cyclopropane ring, presents the chief source of methoxylated photoproducts at low temperatures in methanol.
Cuppen, Th. J. H. M.; Berendsen, N.; Laarhoven, W. H., Recueil des Travaux Chimiques des Pays-Bas, 1990, vol. 109, # 3, p. 168 - 171
作者:Cuppen, Th. J. H. M.、Berendsen, N.、Laarhoven, W. H.
DOI:——
日期:——
The metal-ammonia reduction of mono- and dinaphthylbenzenes