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Luiz F Silva - One of the best experts on this subject based on the ideXlab platform.
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iodine iii mediated ring contraction of 1 2 Dihydronaphthalenes mechanistic insight by computational investigations
ChemistrySelect, 2016Co-Authors: Vitor Menezes H Da Silva, Luiz F Silva, Ataualpa A C BragaAbstract:The metal-free synthesis of the trans-1,3-disubstituted indanes through the ring contraction of 1,2-dihydronaphtalenes, promoted by PhI(OH)Ts (HTIB or Koser's reagent), was computationally studied using Density Functional Theory (DFT) methods. DFT calculations suggest that the stereoselectivity of these reactions arises through the torsional effects during the electrophilic addition of the hypervalent iodine to the double bond of the 1,2-dihydronaphthalene. Furthermore, the fundamental role played by the solvent (MeOH) during the nucleophilic addition step was analyzed by DFT methods on a mixed continuum-microsolvation model system.
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Ring Contraction of 1,2-Dihydronaphthalenes Promoted by Thallium(III) in Acetonitrile: A Diastereoselective Approach to Indanes
Synthesis, 2009Co-Authors: Helena M. C. Ferraz, Vânia M. T. Carneiro, Luiz F SilvaAbstract:trans-1,3-Disubstituted indanes are conveniently accessed by a stereoselective ring contraction of 1,2-Dihydronaphthalenes upon treatment with thallium(III) nitrate (TTN) in acetonitrile. Under these conditions, the oxidative rearrangement of either di- or trisubstituted double bonds is possible.
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iodine iii promoted ring contraction of 1 2 Dihydronaphthalenes a diastereoselective total synthesis of indatraline
Organic Letters, 2007Co-Authors: Luiz F Silva, Eliane C. Pedrozo, Fabiana Y. M. Vieira, Fernanda A. Siqueira, Antonio C. DoriguettoAbstract:A new approach for the synthesis of (±)-indatraline, which is a 3-phenyl-1-indanamine that displays several biological activities, is described. The strategy features as the key step a diastereoselective ring contraction of a 1,2-dihydronaphthalene promoted by PhI(OTs)OH, to construct the indan ring system. The oxidative rearrangement of other 1,2-Dihydronaphthalenes was also investigated, generalizing this method to obtain indans.
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Thallium trinitrate-mediated ring contraction of 1,2-Dihydronaphthalenes: the effect of electron-donating and electron-withdrawing groups
Journal of the Brazilian Chemical Society, 2005Co-Authors: Luiz F Silva, Helena M. C. Ferraz, Raquel M. F. Sousa, Andrea M. AguilarAbstract:The oxidation of a series of 1,2-Dihydronaphthalenes substituted in the aromatic ring was investigated with thallium trinitrate (TTN) in methanol or in trimethylorthoformate (TMOF) as solvent. In all cases, indans are produced, although the yield varied from excellent to poor, depending on the structure of the substrate. The presence of an electron-donating group in the substrate favors the rearrangement, whereas significant amounts of glycolic derivatives, as well as naphthalenes, were obtained in the oxidation of 1,2-Dihydronaphthalenes bearing electron-withdrawing groups, such as Br and NO2. Mechanisms for the formation of each of these products are proposed.
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Thallium trinitrate-mediated ring contraction of 1,2-Dihydronaphthalenes: an approach to the synthesis of indans
Tetrahedron, 2001Co-Authors: Helena M. C. Ferraz, Luiz F Silva, Tiago O. VieiraAbstract:Abstract Oxidation of 1,2-Dihydronaphthalenes with thallium trinitrate was studied. 1,2-dihydronaphthalene, 1-methyl-1,2-dihydronaphthalene, 6- and 8-methoxy-1,2-Dihydronaphthalenes gave rise to the respective ring contraction products in good yields, whereas the rearrangement was not observed using 4-methyl-1,2-dihydronaphthalene and 1-n-butyl-4-methyl-1,2-dihydronaphthalene as substrates.
Yu Liu - One of the best experts on this subject based on the ideXlab platform.
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copper promoted cyanoalkylation ring expansion of vinylcyclopropanes with α c h bonds in alkylnitriles toward 3 4 Dihydronaphthalenes
Organic and Biomolecular Chemistry, 2020Co-Authors: Zan Chen, Quan Zhou, Qingnan Chen, Pu Chen, Biquan Xiong, Yun Liang, Kewen Tang, Jun Xie, Yu LiuAbstract:A copper-promoted oxidative cyanomethylation/ring-expansion of vinylcyclopropanes with α-C(sp3)–H bonds in alkyl nitriles is established for the generation of 1-cyanoethylated 3,4-Dihydronaphthalenes. This cyanomethylation/ring-expansion involves a radical pathway and proceeds via cyanomethyl radical formation, radical addition and ring-expansion. This ring-expansion strategy offers a highly atom-economical route for the construction of nitrile-containing 3,4-Dihydronaphthalenes, which can be transformed into other useful products under simple conditions.
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visible light photoredox catalyzed dual c c bond cleavage synthesis of 2 cyanoalkylsulfonylated 3 4 Dihydronaphthalenes through the insertion of sulfur dioxide
Chemical Communications, 2020Co-Authors: Yu Liu, Zan Chen, Biquan Xiong, Qiaolin Wang, Panliang Zhang, Kewen TangAbstract:An efficient novel visible-light photoredox-catalyzed dual carbon–carbon bond cleavage of methylenecyclopropanes and cycloketone oximes for the synthesis of 2-cyanoalkylsulfonated 3,4-Dihydronaphthalenes through the insertion of sulfur dioxide is established. This dual cleavage of carbon–carbon bonds involves a radical pathway and goes through a sequence of iminyl radical formation, carbon–carbon bond cleavage, sulfur dioxide insertion, sulfonyl radical addition, another carbon–carbon bond cleavage, and intramolecular cyclization.
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synthesis of 2 acyl 3 4 Dihydronaphthalenes by silver promoted oxidative c c σ bond acylation arylation of alkylidenecyclopropanes with α ketoacids
Journal of Organic Chemistry, 2019Co-Authors: Yu Liu, Zan Chen, Biquan Xiong, Qiaolin Wang, Congshan Zhou, Changan Yang, Kewen TangAbstract:A novel and efficient AgNO3-facilitated oxidative C–C σ-bond difunctionalization of alkylidenecyclopropanes with α-ketoacids for preparing 2-acyl-substituted 3,4-Dihydronaphthalenes is developed. T...
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metal free oxidative c c bond functionalization of methylenecyclopropanes with ethers leading to 2 substituted 3 4 Dihydronaphthalenes
Journal of Organic Chemistry, 2017Co-Authors: Yu Liu, Biquan Xiong, Qiaolin Wang, Congshan Zhou, Changan Yang, Panliang Zhang, Kewen TangAbstract:A novel metal-free oxidative ring-opening/cyclization of methylenecyclopropanes with ethers was established for the synthesis of diverse 2-substituted 3,4-Dihydronaphthalenes with high selectivity and efficiency. This oxidative cyclization is achieved by C(sp3)-H functionalization, ring-opening, and cyclization, and this method represents a new example of methylenecyclopropane oxidative cyclization with an aromatic carbon and a C(sp3)-H bond by simultaneously forming two new carbon–carbon bonds.
Kewen Tang - One of the best experts on this subject based on the ideXlab platform.
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copper promoted cyanoalkylation ring expansion of vinylcyclopropanes with α c h bonds in alkylnitriles toward 3 4 Dihydronaphthalenes
Organic and Biomolecular Chemistry, 2020Co-Authors: Zan Chen, Quan Zhou, Qingnan Chen, Pu Chen, Biquan Xiong, Yun Liang, Kewen Tang, Jun Xie, Yu LiuAbstract:A copper-promoted oxidative cyanomethylation/ring-expansion of vinylcyclopropanes with α-C(sp3)–H bonds in alkyl nitriles is established for the generation of 1-cyanoethylated 3,4-Dihydronaphthalenes. This cyanomethylation/ring-expansion involves a radical pathway and proceeds via cyanomethyl radical formation, radical addition and ring-expansion. This ring-expansion strategy offers a highly atom-economical route for the construction of nitrile-containing 3,4-Dihydronaphthalenes, which can be transformed into other useful products under simple conditions.
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visible light photoredox catalyzed dual c c bond cleavage synthesis of 2 cyanoalkylsulfonylated 3 4 Dihydronaphthalenes through the insertion of sulfur dioxide
Chemical Communications, 2020Co-Authors: Yu Liu, Zan Chen, Biquan Xiong, Qiaolin Wang, Panliang Zhang, Kewen TangAbstract:An efficient novel visible-light photoredox-catalyzed dual carbon–carbon bond cleavage of methylenecyclopropanes and cycloketone oximes for the synthesis of 2-cyanoalkylsulfonated 3,4-Dihydronaphthalenes through the insertion of sulfur dioxide is established. This dual cleavage of carbon–carbon bonds involves a radical pathway and goes through a sequence of iminyl radical formation, carbon–carbon bond cleavage, sulfur dioxide insertion, sulfonyl radical addition, another carbon–carbon bond cleavage, and intramolecular cyclization.
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synthesis of 2 acyl 3 4 Dihydronaphthalenes by silver promoted oxidative c c σ bond acylation arylation of alkylidenecyclopropanes with α ketoacids
Journal of Organic Chemistry, 2019Co-Authors: Yu Liu, Zan Chen, Biquan Xiong, Qiaolin Wang, Congshan Zhou, Changan Yang, Kewen TangAbstract:A novel and efficient AgNO3-facilitated oxidative C–C σ-bond difunctionalization of alkylidenecyclopropanes with α-ketoacids for preparing 2-acyl-substituted 3,4-Dihydronaphthalenes is developed. T...
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metal free oxidative c c bond functionalization of methylenecyclopropanes with ethers leading to 2 substituted 3 4 Dihydronaphthalenes
Journal of Organic Chemistry, 2017Co-Authors: Yu Liu, Biquan Xiong, Qiaolin Wang, Congshan Zhou, Changan Yang, Panliang Zhang, Kewen TangAbstract:A novel metal-free oxidative ring-opening/cyclization of methylenecyclopropanes with ethers was established for the synthesis of diverse 2-substituted 3,4-Dihydronaphthalenes with high selectivity and efficiency. This oxidative cyclization is achieved by C(sp3)-H functionalization, ring-opening, and cyclization, and this method represents a new example of methylenecyclopropane oxidative cyclization with an aromatic carbon and a C(sp3)-H bond by simultaneously forming two new carbon–carbon bonds.
Yoshinari Sawama - One of the best experts on this subject based on the ideXlab platform.
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biaryl synthesis by ring opening friedel crafts arylation of 1 4 epoxy 1 4 Dihydronaphthalenes catalyzed by iron trichloride
ChemInform, 2015Co-Authors: Yoshinari Sawama, Yasunari Monguchi, Takahiro Kawajiri, Shota Asai, Hironao SajikiAbstract:A highly regioselective iron-catalyzed Friedel—Crafts Arylation of 1,4-epoxy-1,4-Dihydronaphthalenes is presented.
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biarylmethane and fused heterocyclic arene synthesis via in situ generated o and or p naphthoquinone methides
Journal of Organic Chemistry, 2015Co-Authors: Yoshinari Sawama, Yasunari Monguchi, Takahiro Kawajiri, Shota Asai, Naoki Yasukawa, Yuko Shishido, Hironao SajikiAbstract:o- and/or p-naphthoquinone methides (NQMs) can be selectively prepared by the ring opening of 1-(siloxymethyl)-1,4-epoxy-1,4-dihydronaphthalene derivatives based on a substituent effect at the 4 position of the substrates. The 4-alkyl- or silyl-substituted 1-(siloxymethyl)-1,4-epoxy-1,4-dihydronaphthalene was transformed to o-NQM (1-naphthoquinone-2-methide), which underwent Friedel–Crafts 1,4-addition of the α,β-unsaturated carbonyl moiety to provide the 2-benzyl-1-naphthol as the biarylmethane and [4 + 2]-cycloaddition with a dienophile to give the fused heterocyclic arene. Meanwhile, the 4-unsubstituted 1-(siloxymethyl)-1,4-epoxy-1,4-dihydronaphthalene could be converted to the corresponding 4-benzyl-1-naphthol by the Friedel–Crafts 1,6-addition of p-NQM (1-naphthoquinone-4-methide) generated by the site-selective ring opening of the 1,4-epoxy moiety. Furthermore, the 4-(siloxymethyl)-(1,4-bis(siloxymethyl))-1,4-epoxy-1,4-dihydronaphthalene was transformed into a 2,4-bisbenzyl-1-naphthol or pentacyclic...
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lewis acid catalyzed ring opening functionalizations of 1 4 epoxy 1 4 Dihydronaphthalenes
Advanced Synthesis & Catalysis, 2013Co-Authors: Yoshinari Sawama, Koichi Kawamoto, Hiroyuki Satake, Yuta Ogata, Kyoshiro Shibata, Yasunari Monguchi, Hironao Sajiki, Yasuyuki KitaAbstract:Since 1,4-epoxy-1,4-Dihydronaphthalenes are smoothly converted to 1-naphthol derivatives via unstable cation intermediates formed by the acid-catalyzed ring-opening reaction of the 1,4-epoxy moiety of 1,4-epoxy-1,4-Dihydronaphthalenes, their nucleophilic functionalization using the cation intermediates as an active species is extremely difficult. We have accomplished the Lewis acid-catalyzed carbon-carbon and carbon-nitrogen bond formations associated with the ring-opening of 1,4-epoxy-1,4-Dihydronaphthalenes using nucleophiles such as allyltrimethylsilanes, trimethylsilyl cyanide and trimetylsilyl azide, by using the stabilization effect of the cation intermediate based on the introduction of appropriate substituents into the bridgehead positions of 1,4-epoxy-1,4-Dihydronaphthalenes to give the corresponding unique and multifunctionalized naphthalene derivatives. The present reactions could provide excellent regioselective functionalization methods using unsymmetrical substrates, which are quite difficult to achieve using transition metal-induced procedures.
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Regioselective Gold-CatalyzedAllylative Ring Opening of 1,4-Epoxy-1,4-Dihydronaphthalenes
Synlett, 2010Co-Authors: Yoshinari Sawama, Koichi Kawamoto, Hiroyuki Satake, Norbert Krause, Yasuyuki KitaAbstract:In the presence of a gold catalyst, the ring opening of 1,4-epoxy-1,4-Dihydronaphthalenes with allyltrimethylsilane affords allylnaphthalenes in high yield. For unsymmetrical substrates, high regioselectivity is observed in many cases. This reaction might proceed via tricyclic tetrahydrofuran intermediates which are formed stereoselectively.
Yasuyuki Kita - One of the best experts on this subject based on the ideXlab platform.
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lewis acid catalyzed ring opening functionalizations of 1 4 epoxy 1 4 Dihydronaphthalenes
Advanced Synthesis & Catalysis, 2013Co-Authors: Yoshinari Sawama, Koichi Kawamoto, Hiroyuki Satake, Yuta Ogata, Kyoshiro Shibata, Yasunari Monguchi, Hironao Sajiki, Yasuyuki KitaAbstract:Since 1,4-epoxy-1,4-Dihydronaphthalenes are smoothly converted to 1-naphthol derivatives via unstable cation intermediates formed by the acid-catalyzed ring-opening reaction of the 1,4-epoxy moiety of 1,4-epoxy-1,4-Dihydronaphthalenes, their nucleophilic functionalization using the cation intermediates as an active species is extremely difficult. We have accomplished the Lewis acid-catalyzed carbon-carbon and carbon-nitrogen bond formations associated with the ring-opening of 1,4-epoxy-1,4-Dihydronaphthalenes using nucleophiles such as allyltrimethylsilanes, trimethylsilyl cyanide and trimetylsilyl azide, by using the stabilization effect of the cation intermediate based on the introduction of appropriate substituents into the bridgehead positions of 1,4-epoxy-1,4-Dihydronaphthalenes to give the corresponding unique and multifunctionalized naphthalene derivatives. The present reactions could provide excellent regioselective functionalization methods using unsymmetrical substrates, which are quite difficult to achieve using transition metal-induced procedures.
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Regioselective Gold-CatalyzedAllylative Ring Opening of 1,4-Epoxy-1,4-Dihydronaphthalenes
Synlett, 2010Co-Authors: Yoshinari Sawama, Koichi Kawamoto, Hiroyuki Satake, Norbert Krause, Yasuyuki KitaAbstract:In the presence of a gold catalyst, the ring opening of 1,4-epoxy-1,4-Dihydronaphthalenes with allyltrimethylsilane affords allylnaphthalenes in high yield. For unsymmetrical substrates, high regioselectivity is observed in many cases. This reaction might proceed via tricyclic tetrahydrofuran intermediates which are formed stereoselectively.