- Catalyst-Controlled Regioselective Chlorination of Phenols and Anilines through a Lewis Basic Selenoether Catalyst
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We report a highly efficient ortho-selective electrophilic chlorination of phenols utilizing a Lewis basic selenoether catalyst. The selenoether catalyst resulted in comparable selectivities to our previously reported bis-thiourea ortho-selective catalyst, with a catalyst loading as low as 1%. The new catalytic system also allowed us to extend this chemistry to obtain excellent ortho-selectivities for unprotected anilines. The selectivities of this reaction are up to >20:1 ortho/para, while the innate selectivities for phenols and anilines are approximately 1:4 ortho/para. A series of preliminary studies revealed that the substrates require a hydrogen-bonding moiety for selectivity.
- Dinh, Andrew N.,Maddox, Sean M.,Vaidya, Sagar D.,Saputra, Mirza A.,Nalbandian, Christopher J.,Gustafson, Jeffrey L.
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p. 13895 - 13905
(2020/11/03)
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- Regioselective Oxidative Chlorination of Arenols Using NaCl and Oxone
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We developed a practical and environmentally benign method for the chlorinative dearomatization of arenols using transient electrophilic chlorinating species generated in situ from inexpensive sodium chloride and Oxone as a Cl source and oxidant, respectively, under mild conditions. Moreover, the regioselective chlorination or chlorinative dearomatization of 1-naphthols was also achieved by changing the reaction conditions.
- Uyanik, Muhammet,Sahara, Naoto,Ishihara, Kazuaki
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supporting information
p. 27 - 31
(2018/10/25)
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- Ammonium Salt-Catalyzed Highly Practical Ortho-Selective Monohalogenation and Phenylselenation of Phenols: Scope and Applications
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An ortho-selective ammonium chloride salt-catalyzed direct C-H monohalogenation of phenols and 1,1′-bi-2-naphthol (BINOL) with 1,3-dichloro-5,5-dimethylhydantoin (DCDMH) as the chlorinating agent has been developed. The catalyst loading was low (down to 0.01 mol %) and the reaction conditions were very mild. A wide range of substrates including BINOLs were compatible with this catalytic protocol. Chlorinated BINOLs are useful synthons for the synthesis of a wide range of unsymmetrical 3-aryl BINOLs that are not easily accessible. In addition, the same catalytic system can facilitate the ortho-selective selenylation of phenols.
- Xiong, Xiaodong,Yeung, Ying-Yeung
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p. 4033 - 4043
(2018/05/22)
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- A succinct synthesis of the vaulted biaryl ligand vanol via a dienone-phenol rearrangement
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Vanol is a member of the vaulted biaryl family of ligands and it has been proven to be very effective in a number of asymmetric catalytic reactions. The previous synthesis of vanol, while effective, is limited by the cost of reagents involved. The present work evaluates three different approaches to the synthesis of 3-phenyl-1-naphthol, a key intermediate in the synthesis of vanol. The first approach has its key step as the Michael addition of a benzyl Grignard to methyl cinnamate. In the second approach the key step is the first step, a Reformatsky reaction of ethyl bromoacetate and deoxybenzoin. The final and most-efficient approach involves a dienone-phenol rearrangement of a 4-aryl-1-tetralenone generated in-situ from the reaction of 4-chloro-1-naphthol with AlCl3 and benzene, and preliminary results are reported on the extension of this method to substituted vanol derivatives.
- Ding, Zhensheng,Xue, Song,Wulff, William D.
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scheme or table
p. 2130 - 2146
(2011/10/18)
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- Lewis acid catalyzed highly selective halogenation of aromatic compounds
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A simple and efficient procedure for the halogenation of aromatic compounds with NCS, NBS, NIS and NFSI in the presence of catalytic amount of ZrCl 4 is described. Chlorination, bromination, iodination and fluorination of various aromatic compounds are performed with high selectivity under mild reaction conditions. Georg Thieme Verlag Stuttgart.
- Zhang, Yanhua,Shibatomi, Kazutaka,Yamamoto, Hisashi
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p. 2837 - 2842
(2007/10/03)
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- PHOTOCHEMISTRY OF α-HALOCYCLOALKANONES AND α,α-DIHALOCYCLOALKANONES. IONIC AND RADICAL PHOTOCHEMICAL CARBON-HALOGEN BOND CLEAVAGE
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The nature of the photochemical carbon-halogen bond cleavage in α-halo cycloalkanones depends on the halogen atom bonded and on the ring size of the cycloalkanone.In the 2-halo-1-indanone series the amount of radical products increased from iodine to chlorine, while in the case of 2-halo-3,4-dihydro-1(2H)-naphthalenone 43percent for iodo, 32percent for bromo, and 53percent for the chloro derivative were found.On the other hand, photochemical carbon-chlorine bond cleavage in 2,2-dichloro-1-indanone led to only radical products, while the formation of both radical and ionic products inthe ratio 1:1 was observed in the case of 2,2-dibromo-1-indanone.In the 2,2-dihalo-3,4-dihydro-1(2H)-naphthalenone series, the ratio of the radical to ionic products formed strongly depended on the halogen atom bonded: preferential formation of the radical product in the case of the chloro derivative (92percent) in contrast to 94percent of the ionic products in the case of the bromoderivative, was observed.
- Sket, Boris,Zupan, Marko
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p. 1745 - 1752
(2007/10/02)
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- Carbonyl Oxide Chemistry. The NIH Shift
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Benzophenone oxide has been shown to oxidize 1-chloronaphthalene and p-xylene with accompanying NIH shift of chlorine and methyl, respectively.Similar oxidation of toluene leads to a mixture of o-,p-, and m-cresols while N-acetyl-L-phenylalanine ethyl ester is oxidized to the corresponding tyrosine derivative.The results are discussed in terms of their relationship to the "activation" of polycyclic aromatic hydrocarbons in polluted atmospheres and the possible production of mutagens/carcinogens.
- Kumar, S.,Murray, R. W.
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p. 1040 - 1045
(2007/10/02)
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- HALOGENATION REGIOSELECTIVE EN SERIE AROMATIQUE-II CHLORATION DES NAPHTOLS ET LEURS ETHERS A L'AIDE DE REACTIFS METTANT EN JEU DES INTERACTIONS DU TYPE DONNEUR-ACCEPTEUR
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The regispecific chlorination of naphtols by hexachlorocyclohexadienones as selective chlorinating reagents is described.The selectivity attained is better than that which we have obtained with phenol derivatives and confirms the importance of the donor-acceptor interaction between the reagent and the naphthol during the chlorination.
- Guy, Alain,Lemaire, Marc,Guette, Jean-Paul
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p. 2347 - 2354
(2007/10/02)
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- CONDENSATION OF PHENOLS AND THEIR DERIVATIVES WITH AROMATIC COMPOUNDS IN THE PRESENCE OF ACIDIC AGENTS. V. REACTIONS OF CHLORINE-SUBSTITUTED NAPHTHOLS WITH BENZENE
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Substitution of the chlorine at position 1 by a phenyl residue occurs readily in the reaction of 1-chloro- and 1,4-dichloro-2-naphthols with benzene in the presence of aluminum chloride and hydrogen chloride. 4-Chloro-2-naphthol reacts with considerably great difficulty, giving a small yield of 4-phenyl-2-naphthol.The possibility of using a mixture of 4- and 2-chloro-1-naphthols for the production of 3-phenyl-1-naphthol was demonstrated.The possible reaction paths are discussed.
- Repinskaya, I. B.,Savel'ev, V. A.,Makarova, Z. S.,Koptyug, V. A.
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p. 1463 - 1466
(2007/10/02)
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- Spirans. Part 13. The Synthesis and Orientation of Spirans related to Abel's Ketone (Naphthofuran-2(1H)-spiro-1'(2'H)-naphthalen-2'-one)
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The aryl substituents in the stereoisomers (2) and (3) of 1-phenylnaphthofuran-2(1H)-spiro-1'(2'H)-naphthalen-2'-one are subject to hindered rotation by an energy barrier of ca. 15 kcal mol-1.If the phenyl substituent carries an ortho substituent, however, rotation is prevented at temperatures up to 60 deg C (the highest examined): only one rotamer is obtainable (the other is too crowded) and it has the ortho-substituent cisoid with respect to the triarylmethine proton. The temperature-variable broadening of the signals from the protons of the aryl substituent serves to identify these in the 1H n.m.r. spectra.Some other resonances can be regularly identified by combinations of coupling constants, double-irradiation experiments, and shifts induced by using benzene instead of trichloromethane as sovent, but the only one of value for determining the configuration at the triarylmethine centre is that already known, i.e. the upfield shift in the resonance of the vinylic (3') proton caused by the aryl substituent when this lies immediately below it.A less precise but more general test of configuration is afforded by the mutual shielding of the aryl substituent and ring E when these are in adjacent planes. Methods of preparation are given for several related spirans, especially those containing the spiro-1'(4'H)-naphthalen-4'-one nucleus, and n.m.r. methods used to establish the configurations.
- Dean, Francis M.,Herbin, G. Antonio,Matkin, David A.,Price, Anthony W.,Robinson, Malcolm L.
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p. 1986 - 1993
(2007/10/02)
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