- Metal-free cycloisomerizations of: O -alkynylbiaryls
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We describe a novel and highly efficient metal-free strategy to construct 9,9-disubstituted fluorenes and phenanthrenes via the TfOH-catalyzed cycloisomerizations of o-alkynylbiaryls. Notably, the significant effects of the electronic properties and steric hindrance of the alkyne terminus on the reaction selectivity have been observed.
- Zhang, Jingyi,Li, Siqi,Qiao, Yan,Peng, Cheng,Wang, Xiao-Na,Chang, Junbiao
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supporting information
p. 12455 - 12458
(2018/11/20)
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- Iridium-Catalyzed Formal [4 + 1] Cycloaddition of Biphenylenes with Alkenes Initiated by C-C Bond Cleavage for the Synthesis of 9,9-Disubstituted Fluorenes
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An Ir-catalyzed intermolecular reaction of biphenylenes as a C4 unit with various alkenes as a C1 unit gave 9,9-disubstituted fluorenes in moderate to high yields. Preliminary mechanistic studies revealed that this formal [4 + 1] cycloaddition probably pr
- Takano, Hideaki,Kanyiva, Kyalo Stephen,Shibata, Takanori
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p. 1860 - 1863
(2016/05/19)
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- Direct C-H bond arylation of fluorenes with aryl chlorides catalyzed by N-heterocyclic carbene-palladium(ii)-1-methylimidazole complex and further transformation of the products in a one-pot procedure
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We report here the NHC-Pd(ii)-Im complex 1-catalyzed direct C-H bond functionalization of the C9 position of fluorenes with aryl chlorides and further transformation of the resulting products in a one-pot procedure. Under the optimal conditions, arylated fluorenes can be obtained in moderate to almost quantitative yields using various activated and unactivated (hetero)aryl chlorides as the arylating reagents. Furthermore, if the mixture from the arylation reaction is exposed to air, the C9-oxidized products can be obtained in acceptable to good yields in a one-pot procedure. In addition, alkyl groups can also be efficiently introduced to the above mixture from the arylation reaction, producing further C9-alkylated products in good to almost quantitative yields in a one-pot procedure, thus providing an expedient, inexpensive and practical strategy for the mono- and di-functionalization of fluorenes. This journal is
- Ji, Ya-Yun,Lu, Li-Li,Shi, Yu-Chun,Shao, Li-Xiong
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p. 8488 - 8498
(2014/12/10)
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- Palladium-Catalyzed Methylation of Aryl and Vinyl Halides by Stabilized Methylaluminum and Methylgallium Complexes
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The intramolecularly stabilized mono- and dialkylaluminum complexes 1a, 2, 3, 4a, 5a, 5c, 6a, 6c, 7, 8, and 9 in the presence of palladium catalysts, cross-alkylate aryl, vinyl, and benzyl bromides and iodides under mild standard laboratory conditions. Aryl bromides with carbonyl substituents or benzylic halides are converted partially into dialkyl compounds. Under similar conditions, the analogous stabilized dimethylgallium complexes 1b, 4b, 5b, 6b, and 10 methylate aryl and vinyl bromides and iodides in a highly selective manner. Substituted bromobenzenes XC6H4Br, where X = CHO, COPh, CO2Et, CN, NO2, Cl, CH2Br, or CH=CHCOPh, are methylated by the organogallium reagents usually only at the aromatic ring halogen atom to give substituted toluenes as single products. The methylation rates were shown to depend on the nature of the chelating ligands, on the solvent, and on the type of palladium catalyst employed.
- Blum, Jochanan,Gelman, Dmitri,Baidossi, Wael,Shakh, Eduard,Rosenfeld, Ayelet,Aizenshtat, Zeev,Wassermann, Birgit C.,Frick, Michael,Heymer, Bernd,Schutte, Stefan,Wernik, Sonja,Schumann, Herbert
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p. 8681 - 8686
(2007/10/03)
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- The One-electron Oxidation of Biphenyl-2-ylethylenes. Subsequent Chemical Reactivity Controlled by Electron Return or Proton Transfer
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Biphenyl-2-ylethylenes react with (4-BrC6H4)3N.+SbCl6- to give the radical cation of the electrocyclization product which initiates a protic catalysis to the related flourenes or, in presence of 2,6-di-t-butylpyridine or water, lead
- Lapouyade, Rene,Villeneuve, Patrice,Nourmamode, Aziz,Morand, Jean-Pierre
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p. 776 - 778
(2007/10/02)
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