The Experts below are selected from a list of 5709 Experts worldwide ranked by ideXlab platform
Yongjun Chen - One of the best experts on this subject based on the ideXlab platform.
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Organocatalytic enantioselective Friedel–Crafts Alkylation of simple phenols with trifluoropyruvate
Tetrahedron Letters, 2008Co-Authors: Jun-ling Zhao, Dong Wang, Li Liu, Yongjun ChenAbstract:Abstract Enantioselective Friedel–Crafts Alkylation of simple phenols (4a–j) with 3,3,3-trifluoropyruvate (3) was accomplished by using chiral cinchona alkaloid catalyst 2h (10 mol %). High yields and enantioselectivities (71–94% ee) of the Friedel–Crafts Alkylation products were obtained.
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tfa mediated tandem friedel crafts Alkylation cyclization hydrogen transfer process for the synthesis of flavylium compounds
Journal of Organic Chemistry, 2007Co-Authors: Yanchao Wu, Dong Wang, Yongjun ChenAbstract:The tandem reaction of phenols and chalcones in refluxing TFA gave the flavylium species of 2-hydroxy-2-phenyl-2H-chromenes in moderate to good isolated yields. The reaction was proposed to involve a tandem transformation of Friedel−Crafts Alkylation, dehydrative cyclization, intermolecular hydrogen transfer, and hydration. As a multifunctional catalyst, TFA mediated the processes efficiently and cleanly.
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TFA-mediated tandem Friedel-Crafts Alkylation/cyclization/hydrogen transfer process for the synthesis of flavylium compounds.
Journal of Organic Chemistry, 2007Co-Authors: Yanchao Wu, Dong Wang, Yongjun ChenAbstract:The tandem reaction of phenols and chalcones in refluxing TFA gave the flavylium species of 2-hydroxy-2-phenyl-2H-chromenes in moderate to good isolated yields. The reaction was proposed to involve a tandem transformation of Friedel−Crafts Alkylation, dehydrative cyclization, intermolecular hydrogen transfer, and hydration. As a multifunctional catalyst, TFA mediated the processes efficiently and cleanly.
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catalytic and highly enantioselective friedel crafts Alkylation of aromatic ethers with trifluoropyruvate under solvent free conditions
Organic Letters, 2006Co-Authors: Jun-ling Zhao, And Dong Wang, Yongjun ChenAbstract:Highly enantioselective Friedel−Crafts Alkylation of simple and aromatic ethers (4a−l) with 3,3,3-trifluoropyruvate (3) was accomplished by using chiral (4R,5S)-DiPh-BOX(1b)−Cu(OTf)2 complex (1 mol %) as a catalyst under solvent-free conditions. Excellent yields and enantioselectivities (90−93% ee, after recrystallization up to 99% ee) of the Friedel−Crafts Alkylation products were obtained.
Yujian He - One of the best experts on this subject based on the ideXlab platform.
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hypercrosslinked porous polycarbazoles via one step oxidative coupling reaction and friedel crafts Alkylation
Polymer Chemistry, 2015Co-Authors: Qi Chen, Jiaguo Yu, Yujian HeAbstract:Considering that carbazolyl groups can be coupled through FeCl3-promoted oxidative coupling reaction and vinyl/hydroxymethyl-carrying phenyl groups can be linked by FeCl3-catalyzed Friedel–Crafts Alkylation, a facile method for the preparation of hypercrosslinked carbazole-based porous organic polymers (CPOP-16–19) via FeCl3-promoted one-step oxidative coupling reaction and Friedel–Crafts Alkylation from the vinyl or hydroxymethyl functionalized carbazole monomers is reported. The Brunauer–Emmett–Teller specific surface area of the obtained polymers is up to 1130 m2 g−1, which is comparable to the other reported hypercrosslinked porous polymers. From their gas adsorption isotherms, the hydrogen uptake capacity of CPOP-19 is high up to 2.39 wt% at 1.0 bar and 77 K, and the uptake capacity for carbon dioxide of CPOP-19 can reach 16.7 wt% at 1.0 bar and 273 K. Moreover, the adsorption capacity of the obtained materials for poisonous and harmful organic vapors such as toluene and formaldehyde was also investigated. The adsorbed amount of toluene by CPOP-19 is 672 mg g−1 (about 7.3 mmol g−1) at its saturated vapor pressure. Among the prepared polymers, CPOP-19 possesses an excellent adsorption capacity for formaldehyde (11.2 mg g−1) under ambient conditions and exhibits good repeatability at the same time, which suggests its potential application in the removal of harmful small molecules from the environment.
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Hypercrosslinked porous polycarbazoles via one-step oxidative coupling reaction and Friedel–Crafts Alkylation
Polymer Chemistry, 2015Co-Authors: Qi Chen, Jiaguo Yu, Yujian HeAbstract:Considering that carbazolyl groups can be coupled through FeCl3-promoted oxidative coupling reaction and vinyl/hydroxymethyl-carrying phenyl groups can be linked by FeCl3-catalyzed Friedel–Crafts Alkylation, a facile method for the preparation of hypercrosslinked carbazole-based porous organic polymers (CPOP-16–19) via FeCl3-promoted one-step oxidative coupling reaction and Friedel–Crafts Alkylation from the vinyl or hydroxymethyl functionalized carbazole monomers is reported. The Brunauer–Emmett–Teller specific surface area of the obtained polymers is up to 1130 m2 g−1, which is comparable to the other reported hypercrosslinked porous polymers. From their gas adsorption isotherms, the hydrogen uptake capacity of CPOP-19 is high up to 2.39 wt% at 1.0 bar and 77 K, and the uptake capacity for carbon dioxide of CPOP-19 can reach 16.7 wt% at 1.0 bar and 273 K. Moreover, the adsorption capacity of the obtained materials for poisonous and harmful organic vapors such as toluene and formaldehyde was also investigated. The adsorbed amount of toluene by CPOP-19 is 672 mg g−1 (about 7.3 mmol g−1) at its saturated vapor pressure. Among the prepared polymers, CPOP-19 possesses an excellent adsorption capacity for formaldehyde (11.2 mg g−1) under ambient conditions and exhibits good repeatability at the same time, which suggests its potential application in the removal of harmful small molecules from the environment.
Rui Wang - One of the best experts on this subject based on the ideXlab platform.
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Regio- and stereospecific Friedel-Crafts Alkylation of indoles with spiro-epoxyoxindoles.
Organic & biomolecular chemistry, 2018Co-Authors: Guangjun Bao, Liang Hong, Wangsheng Sun, Gongming Zhu, Liwu Huang, Rui WangAbstract:A highly efficient strategy for the regio- and stereospecific Friedel-Crafts Alkylation of indoles with spiro-epoxyoxindoles has been developed in the mixed solvents of HFIP/H2O (1 : 9) without the use of catalysts. This protocol provides an atomically economical, catalyst-free and simple route for the construction of synthetically useful 3-(3-indolyl)-oxindole-3-methanols in high yields. Starting from optically active spiro-epoxyoxindoles a variety of enantiospecific 3-(3-indolyl)-oxindole-3-methanols could be obtained in high yields with complete retention of enantioselectivity.
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Catalytic Kinetic Resolution of Spiro-Epoxyoxindoles with 1‑Naphthols: Switchable Asymmetric Tandem Dearomatization/Oxa-Michael Reaction and Friedel–Crafts Alkylation of 1‑Naphthols at the C4 Position
2018Co-Authors: Gongming Zhu, Liang Hong, Wangsheng Sun, Guangjun Bao, Liwu Huang, Rui WangAbstract:Switching the chemo- or regioselectivity from identical starting materials under readily tunable reaction conditions represents a great challenge in medicinal and synthetic organic chemistry. Herein, we report the asymmetric dearomatization/oxa-Michael reaction and Friedel–Crafts Alkylation of 1-naphthols at the C4 position, wherein the chemoselectivity could be switched easily by using different reaction conditions without changing the catalyst and the substrates. The reactions feature asymmetric Friedel–Crafts Alkylation of 1-naphthols at the C4 position and asymmetric dearomatization without using specific substrates or stepwise protocols
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highly enantioselective friedel crafts Alkylation reaction catalyzed by rosin derived tertiary amine thiourea synthesis of modified chromanes with anticancer potency
Chemical Communications, 2012Co-Authors: Xianxing Jiang, Yanhong Xing, Long Wang, Shoulei Wang, Zongyao Chen, Rui WangAbstract:We present herein for the first time the synthesis and preliminary biological evaluation of various modified chromanesvia a rosin-derived tertiary amine–thiourea-catalyzed highly enantioselective Friedel–Crafts Alkylation reaction.
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Enantioselective Friedel–Crafts Alkylation of 4,7‐Dihydroindoles with Enones Catalyzed by Primary–Secondary Diamines
Chemistry (Weinheim an der Bergstrasse Germany), 2009Co-Authors: Liang Hong, Wangsheng Sun, Chunxia Liu, Lei Wang, Kwok-yin Wong, Rui WangAbstract:A study was conducted to demonstrate the development of a new chiral primary-secondary diamine catalyst derived from amino acid and its application in the asymmetric Friedel-Crafts Alkylation of 4,7-dihydroindoles with α-βunsaturated enones. A array of primary amines derived from amino acids were investigated in the asymmetric Friedel-Crafts Alkylation of 4,7-dihydroindole with benzylideneacetone in toluene. It was found that the length of the alkyl chain influenced the catalytic activity of the primary amine catalyst and the n-propylated catalyst gave the best result. It was also observed that the acid co-catalyst had a great impact on the reaction. The scope and limitations of the method was examined with regard to the enone and 4,7-dihydroindole substrates after establishing optimal reaction conditions.Department of Applied Biology and Chemical Technolog
Dong Wang - One of the best experts on this subject based on the ideXlab platform.
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Organocatalytic enantioselective Friedel–Crafts Alkylation of simple phenols with trifluoropyruvate
Tetrahedron Letters, 2008Co-Authors: Jun-ling Zhao, Dong Wang, Li Liu, Yongjun ChenAbstract:Abstract Enantioselective Friedel–Crafts Alkylation of simple phenols (4a–j) with 3,3,3-trifluoropyruvate (3) was accomplished by using chiral cinchona alkaloid catalyst 2h (10 mol %). High yields and enantioselectivities (71–94% ee) of the Friedel–Crafts Alkylation products were obtained.
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tfa mediated tandem friedel crafts Alkylation cyclization hydrogen transfer process for the synthesis of flavylium compounds
Journal of Organic Chemistry, 2007Co-Authors: Yanchao Wu, Dong Wang, Yongjun ChenAbstract:The tandem reaction of phenols and chalcones in refluxing TFA gave the flavylium species of 2-hydroxy-2-phenyl-2H-chromenes in moderate to good isolated yields. The reaction was proposed to involve a tandem transformation of Friedel−Crafts Alkylation, dehydrative cyclization, intermolecular hydrogen transfer, and hydration. As a multifunctional catalyst, TFA mediated the processes efficiently and cleanly.
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TFA-mediated tandem Friedel-Crafts Alkylation/cyclization/hydrogen transfer process for the synthesis of flavylium compounds.
Journal of Organic Chemistry, 2007Co-Authors: Yanchao Wu, Dong Wang, Yongjun ChenAbstract:The tandem reaction of phenols and chalcones in refluxing TFA gave the flavylium species of 2-hydroxy-2-phenyl-2H-chromenes in moderate to good isolated yields. The reaction was proposed to involve a tandem transformation of Friedel−Crafts Alkylation, dehydrative cyclization, intermolecular hydrogen transfer, and hydration. As a multifunctional catalyst, TFA mediated the processes efficiently and cleanly.
Yanchao Wu - One of the best experts on this subject based on the ideXlab platform.
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tfa mediated tandem friedel crafts Alkylation cyclization hydrogen transfer process for the synthesis of flavylium compounds
Journal of Organic Chemistry, 2007Co-Authors: Yanchao Wu, Dong Wang, Yongjun ChenAbstract:The tandem reaction of phenols and chalcones in refluxing TFA gave the flavylium species of 2-hydroxy-2-phenyl-2H-chromenes in moderate to good isolated yields. The reaction was proposed to involve a tandem transformation of Friedel−Crafts Alkylation, dehydrative cyclization, intermolecular hydrogen transfer, and hydration. As a multifunctional catalyst, TFA mediated the processes efficiently and cleanly.
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TFA-mediated tandem Friedel-Crafts Alkylation/cyclization/hydrogen transfer process for the synthesis of flavylium compounds.
Journal of Organic Chemistry, 2007Co-Authors: Yanchao Wu, Dong Wang, Yongjun ChenAbstract:The tandem reaction of phenols and chalcones in refluxing TFA gave the flavylium species of 2-hydroxy-2-phenyl-2H-chromenes in moderate to good isolated yields. The reaction was proposed to involve a tandem transformation of Friedel−Crafts Alkylation, dehydrative cyclization, intermolecular hydrogen transfer, and hydration. As a multifunctional catalyst, TFA mediated the processes efficiently and cleanly.
