- Acid-promoted selective synthesis of trifluoromethylselenolated benzofurans with Se-(trifluoromethyl) 4-methylbenzenesulfonoselenoate
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A Br?nsted acid-promoted trifluoromethylselenolation of benzofurans was disclosed by using Se-(trifluoromethyl) 4-methylbenzenesulfonoselenoate as a stable and easily prepared electrophilic trifluoromethylselenolating reagent. A wide range of SeCF3-substituted benzofuran derivatives were obtained in moderate to good yields with excellent regioselectivity. The tandem cyclization/trifluoromethylselenolation procedure of 1-methoxy-2-(arylethynyl)benzenes were also realized by engaging FeCl3 as the catalyst.
- Liu, Juyan,Tian, Miaomiao,Li, Ankun,Ji, Liangshuo,Qiu, Di,Zhao, Xia
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supporting information
(2021/02/01)
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- BCl3-Induced Annulative Oxo- and Thioboration for the Formation of C3-Borylated Benzofurans and Benzothiophenes
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BCl3-induced borylative cyclization of aryl-alkynes possessing ortho-EMe (E=S, O) groups represents a simple, metal-free method for the formation of C3-borylated benzothiophenes and benzofurans. The dichloro(heteroaryl)borane primary products can be protected to form synthetically ubiquitous pinacol boronate esters or used in situ in Suzuki–Miyaura cross couplings to generate 2,3-disubstituted heteroarenes from simple alkyne precursors in one pot. In a number of cases alkyne trans-haloboration occurs alongside, or instead of, borylative cyclization and the factors controlling the reaction outcome are determined.
- Warner, Andrew J.,Churn, Anna,McGough, John S.,Ingleson, Michael J.
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supporting information
p. 354 - 358
(2016/12/30)
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- Iridium-Catalyzed Intramolecular Methoxy C?H Addition to Carbon–Carbon Triple Bonds: Direct Synthesis of 3-Substituted Benzofurans from o-Methoxyphenylalkynes
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Catalytic hydroalkylation of an alkyne with methyl ether was accomplished. Intramolecular addition of the C?H bond of a methoxy group in 1-methoxy-2-(arylethynyl)benzenes across a carbon–carbon triple bond took place efficiently either in toluene at 110 °C or in p-xylene at 135 °C in the presence of an iridium catalyst. The initial 5-exo cyclization products underwent double-bond migration during the reaction to give 3-(arylmethyl)benzofurans in high yields.
- Torigoe, Takeru,Ohmura, Toshimichi,Suginome, Michinori
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supporting information
p. 10415 - 10419
(2016/07/21)
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- FeCl3-Diorganyl dichalcogenides promoted cyclization of 2-alkynylanisoles to 3-chalcogen benzo[ b ]furans
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A general synthesis of 3-chalcogen benzo[b]furans from the readily available 2-alkynylanisoles, via FeCl3/diorganyl dichalcogenides intramolecular cyclization, has been developed. Aryl and alkyl groups directly bonded to the chalcogen atom were used as cycling agents. The results revealed that the reaction significantly depends on the electronic effects of substituents in the aromatic ring bonded to the selenium atom of the diselenide species. We observed that the pathway of reaction was not sensitive to the nature of substituents in the aromatic ring of anisole since both the electron-donating and the electron-withdrawing groups delivered the products in similar yields. In addition, the obtained heterocycles were readily transformed to more complex products by using a chalcogen/lithium exchange reaction with n-BuLi followed by trapping of the lithium intermediate with aldehydes, furnishing the desired secondary alcohols in good yields.
- Gay, Rafaela M.,Manarin, Flavia,Schneider, Caroline C.,Barancelli, Daniela A.,Costa, Michael D.,Zeni, Gilson
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supporting information; experimental part
p. 5701 - 5706
(2010/10/03)
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