- Reduction of 1,1'-binaphthyls to octahydro-1,1'-binaphthyl derivatives with Raney Ni-Al alloy in aqueous solution
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Reduction of BINOL, BINAM and NOBIN with Raney Ni-Al alloy in dilute NaOH aqueous solution results in the formation of H8-BINOL, H8-BINAM and H8-NOBIN in 60-86% isolated yields with 97.5-99% enantiomeric excesses. (C) 2000 Elsevier Science Ltd.
- Guo,Ding
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- Partial ring hydrogenation of naphthols over supported metal catalysts in supercritical carbon dioxide solvent
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Selective ring hydrogenation of naphthols to tetrahydronaphthols and tetralones proceeded at 323 K over a charcoal supported rhodium catalyst in supercritical carbon dioxide. Copyright
- Mine, Eiichi,Haryu, Eiji,Arai, Kunio,Sato, Takafumi,Sato, Osamu,Sasaki, Akiyoshi,Rode, Chandrashekhar V.,Shirai, Masayuki
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- Selective partial hydrogenation of hydroxy aromatic derivatives with palladium nanoparticles supported on hydrophilic carbon
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Selective hydrogenation of phenol to cyclohexanol in the aqueous phase was achieved using a new catalytic system based on palladium particles supported on hydrophilic carbon prepared by one-pot hydrothermal carbonisation. The Royal Society of Chemistry.
- Makowski, Philippe,Demir Cakan, Rezan,Antonietti, Markus,Goettmann, Frederic,Titirici, Maria-Magdalena
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- HYDROGENATION AND HYDROGENOLYSIS. XVII. THE SELECTIVITIES OF PLATINUM GROUP METALS IN CATALYTIC HYDROGENATION OF 2-NAPHTHOL AND TETRAHYDRO-2-NAPHTHOLS.
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Catalytic hydrogenation of 2-naphthol (NL) with the six platinum metals has been studied in t-BuOH at 80 degree C and 4-5 MPa H//2 pressure. Selectivities for formation of 1,2,3,4- and 5,6,7,8-tetrahydro-2-naphthols (ac- and ar-TLs) have been determined by application of a kinetic equation. ar-TL was formed more predominantly than ac-TL over all the metals. The hydrogenation of ac- and ar-TLs has also been studied under the same conditions for comparison. The hydrogenation of NL and ar-TL was accompanied by extensive hydrogenolysis to give decalins over Os, Ir, and Pt, whereas the hydrogenolysis occurred only slightly over Ru, Rh, and Pd. In general the hydrogenolysis occurred to much lesser extents with ac-TL. The amounts of 2-decalone formed in hydrogenation of ar-TL have been determined by application of the kinetic equation.
- Nishimura,Ohbuchi,Ikeno,Okada
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- A mild and practical method for deprotection of aryl methyl/benzyl/allyl ethers with HPPh2andtBuOK
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A general method for the demethylation, debenzylation, and deallylation of aryl ethers using HPPh2andtBuOK is reported. The reaction features mild and metal-free reaction conditions, broad substrate scope, good functional group compatibility, and high chemical selectivity towards aryl ethers over aliphatic structures. Notably, this approach is competent to selectively deprotect the allyl or benzyl group, making it a general and practical method in organic synthesis.
- Pan, Wenjing,Li, Chenchen,Zhu, Haoyin,Li, Fangfang,Li, Tao,Zhao, Wanxiang
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p. 7633 - 7640
(2021/09/22)
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- Mild and Selective Rhodium-Catalyzed Transfer Hydrogenation of Functionalized Arenes
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Diboron-mediated rhodium-catalyzed transfer hydrogenation of functionalized arenes is reported. In addition to good functional group tolerance, the reaction features operational simplicity and controllable chemoselectivity. The general applicability of this procedure is demonstrated by the selective hydrogenation of a range of arenes, including functionalized benzenes, biphenyls, and polyaromatics.
- Wang, Yuhan,Chang, Zhiqian,Hu, Yan,Lin, Xiao,Dou, Xiaowei
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supporting information
p. 1910 - 1914
(2021/03/08)
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- Regioselective and Chemoselective Reduction of Naphthols Using Hydrosilane in Methanol: Synthesis of the 5,6,7,8-Tetrahydronaphthol Core
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A regioselective and chemoselective method for catalytic synthesis of biologically interesting 5,6,7,8-tetrahydronaphthols by reduction of naphthols was described. The side aromatic hydrocarbons in naphthols were site-selectively reduced, using hydrosilanes in methanol, allowing for retaining functional phenol scaffolds intact. It presents a rare example of using low-cost and air-stable hydrosilane for catalytic reduction of unactivated aromatic hydrocarbons under mild conditions. This reaction is scalable and proceeds in high selectivity without the formation of 1,2,3,4-tetrahydronaphthol byproducts with toleration of sensitive functionalities such as bromide, chloride, fluoride, ketone, ester, and amide.
- He, Yuan,Tang, Jinghua,Luo, Meiming,Zeng, Xiaoming
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supporting information
p. 4159 - 4163
(2018/07/29)
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- Tuning the Reactivity of Peroxo Anhydrides for Aromatic C-H Bond Oxidation
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Phenol moieties are key structural motifs in many areas of chemical research from polymers to pharmaceuticals. Herein, we report on the design and use of a structurally demanding cyclic peroxide (spiro[bicyclo[2.2.1]heptane-2,4′-[1,2]dioxolane]-3′,5′-dione, P4) for the direct hydroxylation of aromatic substrates. The new peroxide benefits from high thermal stability and can be synthesized from readily available starting materials. The aromatic C-H oxidation using P4 exhibits generally good yields (up to 96%) and appreciable regioselectivities.
- Pilevar, Afsaneh,Hosseini, Abolfazl,?ekutor, Marina,Hausmann, Heike,Becker, Jonathan,Turke, Kevin,Schreiner, Peter R.
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p. 10070 - 10079
(2018/09/06)
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- Synthesis of tetraline derivatives through depolymerization of polyethers with aromatic compounds using a heterogeneous titanium-exchanged montmorillonite catalyst
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A novel depolymerization of poly(tetramethylene glycol) (PTMG) with benzene to tetralin using titanium-exchanged montmorillonite (Ti4+-mont) as a solid acid catalyst is described. This catalyst is applicable to depolymerization of PTMG with some aromatic compounds. This is the first demonstration of the potential use of PTMG as a C4 synthon for organic synthesis.
- Maeno, Zen,Torii, Hiroyuki,Yamada, Shota,Mitsudome, Takato,Mizugaki, Tomoo,Jitsukawa, Koichiro
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p. 89231 - 89233
(2016/10/03)
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- Selective oxidative homo-and cross-coupling of phenols with aerobic catalysts
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Simple catalysts that use atom-economical oxygen as the terminal oxidant to accomplish selective ortho-ortho, ortho-para, or para-para homo-couplings of phenols are described. In addition, chromium salen catalysts have been discovered as uniquely effective in the cross-coupling of different phenols with high chemo-and regioselectivity.
- Lee, Young Eun,Cao, Trung,Torruellas, Carilyn,Kozlowski, Marisa C.
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p. 6782 - 6785
(2014/06/09)
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- CYCLIC PEROXIDE OXIDATION OF AROMATIC COMPOUND PRODUCTION AND USE THEREOF
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The present invention provides a method for converting an aromatic hydrocarbon to a phenol by providing an aromatic hydrocarbon comprising one or more aromatic C-H bonds and one or more activated C-H bonds in a solvent; adding a phthaloyl peroxide to the solvent; converting the phthaloyl peroxide to a di-radical; contacting the di-radical with the one or more aromatic C-H bonds; oxidizing selectively one of the one or more aromatic C-H bonds in preference to the one or more activated C-H bonds; adding a hydroxyl group to the one of the one or more aromatic C-H bonds to form one or more phenols; and purifying the one or more phenols.
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Page/Page column 9; 10
(2014/10/15)
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- Quenched skeletal Ni as the effective catalyst for selective partial hydrogenation of polycyclic aromatic hydrocarbons
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Quenched skeletal Ni is an active and selective catalyst for selective partial hydrogenation of polycyclic aromatic hydrocarbons (PAHs). The molecular structure of PAHs significantly dominate the hydrogenation process and furthermore, the distribution of hydrogenated products.
- Liu, Chengyun,Rong, Zeming,Sun, Zhuohua,Wang, Yong,Du, Wenqiang,Wang, Yue,Lu, Lianhai
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p. 23984 - 23988
(2013/11/19)
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- Metal-free oxidation of aromatic carbon-hydrogen bonds through a reverse-rebound mechanism
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Methods for carbon-hydrogen (C-H) bond oxidation have a fundamental role in synthetic organic chemistry, providing functionality that is required in the final target molecule or facilitating subsequent chemical transformations. Several approaches to oxidizing aliphatic C-H bonds have been described, drastically simplifying the synthesis of complex molecules. However, the selective oxidation of aromatic C-H bonds under mild conditions, especially in the context of substituted arenes with diverse functional groups, remains a challenge. The direct hydroxylation of arenes was initially achieved through the use of strong Bronsted or Lewis acids to mediate electrophilic aromatic substitution reactions with super-stoichiometric equivalents of oxidants, significantly limiting the scope of the reaction. Because the products of these reactions are more reactive than the starting materials, over-oxidation is frequently a competitive process. Transition-metal-catalysed C-H oxidation of arenes with or without directing groups has been developed, improving on the acid-mediated process; however, precious metals are required. Here we demonstrate that phthaloyl peroxide functions as a selective oxidant for the transformation of arenes to phenols under mild conditions. Although the reaction proceeds through a radical mechanism, aromatic C-H bonds are selectively oxidized in preference to activated-H bonds. Notably, a wide array of functional groups are compatible with this reaction, and this method is therefore well suited for late-stage transformations of advanced synthetic intermediates. Quantum mechanical calculations indicate that this transformation proceeds through a novel addition-abstraction mechanism, a kind of 'reverse-rebound' mechanism as distinct from the common oxygen-rebound mechanism observed for metal-oxo oxidants. These calculations also identify the origins of the experimentally observed aryl selectivity.
- Yuan, Changxia,Liang, Yong,Hernandez, Taylor,Berriochoa, Adrian,Houk, Kendall N.,Siegel, Dionicio
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p. 192 - 196
(2013/08/23)
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- One-pot catalysis of dehydrogenation of cyclohexanones to phenols and oxidative Heck coupling: Expedient synthesis of coumarins
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One-pot reactions leading to highly functionalized coumarins have been developed via a Pd(ii)-catalyzed dehydrogenation-oxidative Heck-cyclization process.
- Kim, Donghee,Min, Minsik,Hong, Sungwoo
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supporting information
p. 4021 - 4023
(2013/07/26)
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- A tuneable bifunctional water-compatible heterogeneous catalyst for the selective aqueous hydrogenation of phenols
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A water-tolerant bifunctional heterogeneous catalyst is able to effectively catalyse the selective hydrogenation of phenol to cyclohexanone in water at atmospheric pressure and room temperature with >99.9% selectivity to cyclohexanone at phenol conversions >99.9%. The catalyst was found to be highly active and reusable, giving identical activities and selectivities after >5 uses. Moreover, this reported simple bifunctional catalyst is also able to hydrogenate a range of substituted phenols in high yields under the investigated aqueous conditions. Copyright
- Liu, Hongli,Li, Yingwei,Luque, Rafael,Jiang, Huanfeng
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supporting information; experimental part
p. 3107 - 3113
(2012/01/02)
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- Hydrogenation of phenol in supercritical carbon dioxide catalyzed by palladium supported on Al-MCM-41: A facile route for one-pot cyclohexanone formation
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The hydrogenation of phenol has been carried out in supercritical carbon dioxide (scCO2) under very mild reaction conditions at the temperature of 50°C over palladium supported Al-MCM-41 (metal loading ~1%). This palladium catalyst is shown to be highly active and promotes the selective formation of cyclohexanone (~98%), an industrially important compound, in a "one-pot~ way. The effects of different variables like carbon dioxide and hydrogen pressure, reaction time and also silica/alumina ratio of the MCM-41 support along with palladium dispersion are presented and discussed. The pressure effect of carbon dioxide is significantly prominent in terms of conversion and cyclohexanone selectivity. Moreover, the silica/alumina ratio was also found to be an important parameter to enhance the effectiveness of the catalyst as it exhibits a remarkable increase in phenol conversion from 20.6% to 98.4% as the support changes from only silica MCM-41 to Al-MCM-41. A plausible mechanism for the hydrogenation of phenol to cyclohexanone over the palladium catalyst has been proposed. The proposition is vali-dated by transition state calculations using density functional theory (DFT), which reveal that cyclohexanone is a favorable product and stabilized by -1 over cyclohexanol in ScCO2 medium. Under similar reaction conditions, phenol hydrogenation was also carried out with rhodium, supported on Al-MCM-41. In contrast to the palladium catalyst, a mixture of cyclohexanone (57.8%) and cyclohexanol (42.2%) was formed. Detailed characterization by X-ray diffraction and transmission electron microscopy confirmed the presence of metal nanoparticles (palladium and rhodium) between 10-20 nm. Both the catalysts exhibit strikingly different product distributions in solventless conditions compared to scCO2. This method can also be successfully applied to the other hydroxylated aromatic compounds.
- Chatterjee,Kawanami,Sato,Chatterjee,Yokoyama,Suzuki
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experimental part
p. 1912 - 1924
(2011/03/17)
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- (2,6-Dichloro-4-alkoxyphenyl)-(2,4-dichlorophenyl)methyl trichloroacetimidates: Protection of alcohols and carboxylic acids in solution or on polymer support
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(2,6-Dichloro-4-methoxyphenyl)-(2,4-dichlorophenyl)-methyl trichloroacetimidate can be efficiently activated by TMSOTf (10-100 mol%) to react with alcohols and carboxylic acids. Under these conditions a wide variety of alcohols can be transformed into the corresponding ethers in excellent yields with a slight excess of the trichloroacetimidate. The resulting ethers are not susceptible to typical deprotection conditions for benzyl and 4-methoxybenzyl ether groups, however, they can be conveniently deprotected by treatment with 30-50% trifluoroacetic acid in dichloromethane. Polymer-bound (2,6-dichloro-4-alkoxyphenyl)-(2,4-dichlorophenyl)methyl trichloroacetimidate is useful for immobilization of alcohols and carboxylic acids.
- Kurosu, Michio,Li, Kai
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experimental part
p. 3633 - 3641
(2010/03/05)
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- A new route to substituted phenols by cationic rhodium(l)/BINAP complex-catalyzed decarboxylative [2 + 2 + 2] cycloaddition
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A new route to substituted phenols has been developed by cationic rhodium(l)/BINAP complex-catalyzed decarboxylative [2 + 2 + 2] cycloadditions of 1,6-and 1,7-diynes with commercially available vinylene carbonate.
- Hara, Hiromi,Hirano, Masao,Tanaka, Ken
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scheme or table
p. 1337 - 1340
(2009/08/08)
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- Formal radical closure onto aromatic rings-a general route to carbocycles
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A general method is described for indirectly effecting radical carbocyclization of an alkyl chain onto an aromatic ring. Birch reductive-alkylation of aromatic tert-butyl esters with α,ω- dibromides, chromium(vi)-mediated oxidation of the resulting 1,4-dienes and Finkelstein displacement of Br- with NaI gives cross-conjugated ketones that undergo radical cyclization. The products are easily aromatized to phenols by silylation, Saegusa oxidation and treatment with BiCl 3.H2O. A special feature of the route is that it allows attachment of a substituent to the original aromatic ring in place of the phenolic oxygen of the normal product.
- Clive, Derrick L. J.,Sunasee, Rajesh,Chen, Zhenhua
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experimental part
p. 2434 - 2441
(2009/02/02)
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- Formation of benzo-fused carbocycles by formal radical cyclization onto an aromatic ring
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Equation Presented An indirect method for effecting radical carbocyclization onto aromatic rings is described. Cross-conjugated dienones such as 13, readily prepared by Birch reduction of aromatic fert-butyl esters, in situ alkylation, and oxidation (10 → 11 → 12 → 13), undergo radical cyclization; the products (14) are aromatized by silylation, Saegusa oxidation, and treatment with BiCl3·H2O. A noteworthy feature of this route is that it provides opportunities to attach an additional substituent to the original aromatic ring.
- Clive, Derrick L. J.,Sunasee, Rajesh
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p. 2677 - 2680
(2008/02/09)
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- A NEW PROCESS FOR THE PREPARATION OF PHENOLIC HYDROXY-SUBSTITUTED COMPOUNDS
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The invention relates to a process for the preparation of a phenolic hydroxy-substituted compound of the general formula (I) by desalkylation of an alkyl aryl ether of the general formula (II) by treatment with a thiourea/aluminium chloride reagent pair, in said general formulae R1 stands for straight chain or branched C1-6 alkyl group; R2, R3, R4, R5 , and R6 have the same or different meanings and stand for hydrogen or halogen atom, hydroxy, carboxy, nitro, oxo, C1-6 alkylcarbonyl, straight chain or branched alkyl or - alkoxy, or aryl group, or R2 and R3 together stand for a 5-7 membered ring or fused ring system; said 5-7 membered ring may be a partially saturated ring optionally substituted with an oxo group or can be an unsaturated ring; or said fused ring system may constitute with the first ring a steroid, preferably an estratriene derivative optionally substituted with an oxo or C1-6 alkylcarbonyloxy group in the 17 position -.
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Page/Page column 20
(2008/06/13)
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- Selective hydrogenation of naphthols to tetralones over supported palladium catalysts in supercritical carbon dioxide solvent
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Naphthols were selectively hydrogenated to the corresponding tetralones over supported palladium metal catalysts in supercritical carbon dioxide solvent. Copyright
- Mine, Eiichi,Hiyoshi, Norihito,Sato, Osamu,Rode, Chandrashekhar V.,Shirai, Masayuki
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p. 780 - 781
(2007/10/03)
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- Substituent Effects on Competitive Release of Phenols and 1, 3-Rearrangement in α-Keto Amide Photochemistry
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(Matrix presented) Photolysis of α-keto amides bearing 4-YC 6H4O leaving groups at the position α to the keto group efficiently produces high yields of phenols when Y is an electron-withdrawing group or H. The photoelimination likely
- Ma, Chicheng,Steinmetz, Mark G.
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p. 629 - 632
(2007/10/03)
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- First Carbamates Conversion to Amides by Simple Alkyl Group Transfer from Trialkylalanes
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(Equation presented) N-Monosubstituted carbamates are cleanly converted to amides under treatment with trialkylaluminum. This reaction involves an aluminum-assisted internal delivery of alkyl groups. It can be applied to new and mild protecting group strategies for alcohols.
- El Kaim, Laurent,Grimaud, Laurence,Lee, Anabelle,Perroux, Yannick,Tirla, Cornelia
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p. 381 - 383
(2007/10/03)
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- Organic reaction in water. Part 3: A facile method for reduction of aromatic rings using a Raney Ni-Al alloy in dilute aqueous alkaline solution under mild conditions
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Reduction of aromatic rings such as phenol, naphthalenes, biphenyls, acenaphthene, and acenaphthylene was smoothly performed using a Raney Ni-Al alloy in dilute aqueous alkaline solution without any organic solvents at 90°C under atmospheric pressure, and the corresponding reduced compounds were obtained in high yields. (C) 2000 Elsevier Science Ltd.
- Tsukinoki, Takehito,Kanda, Tadashige,Liu, Guo-Bin,Tsuzuki, Hirohisa,Tashiro, Masashi
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p. 5865 - 5868
(2007/10/03)
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- Hydride-promoted Demethylation of Methyl Phenyl Ethers
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Solutions of L-Selectride or SuperHydride in refluxing THF efficiently deprotect methyl phenyl ethers.L-Selectride is the more effective reagent, while electron-poor arenes work best.Unlike other hydride sources, these reagents permit ether cleavage without the reduction of aryl halides.
- Majetich, George,Zhang, Yong,Wheless, Karen
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p. 8727 - 8730
(2007/10/02)
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- The use of the cyanomethyl unit as a protecting group for phenols, amines and carbamates
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The use of the cyanomethyl unit as a protecting group for phenols, primary and secondary amines, and carbamates is described. Optimized conditions for formation and hydrolysis of cyanomethyl in the presence of the other hydrogenolysis-sensitive groups such as O- and N-benzyl groups are presented.
- Benarab,Boye,Savelon,Guillaumet
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p. 7567 - 7568
(2007/10/02)
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- Metal Arene Complexes in Organic Synthesis. Hydroxylation, Trimethylsilylation, and Carbethoxylation of Some Polycyclic Aromatic Hydrocarbons Utilizing η6-Arene-Chromium Tricarbonyl Complexes
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The deprotonation of polycyclic aromatic hydrocarbon (PAH) chromium tricarbonyl complexes (PAH = naphthalene, anthracene, phenanthrene, pyrene, fluoranthene) using an in situ technique where the PAH complex, the base (LiTMP or LDA), and the electrophile (trialkyl borate, trimethylsilyl chloride, or ethyl chloroformate) were placed in solution simultaneously resulted in hydroxylation, trimethylsilylation, or carbethoxylation of the PAH after oxidative workup where the regiochemistry was controlled by steric factors.As a result, substitution at positions of the PAHs not readily available by electrophilic substitution were obtained in some cases.Conditions minimizing isomer mixtures and factors affecting the regiochemistry and the scope of the reaction sequence were examined.
- Morley, James A.,Woolsey, Neil F.
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p. 6487 - 6495
(2007/10/02)
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- Conversion of 19-Nortestosterone to β-Estradiol
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Selective aromatization of cyclohexenone was achieved via abstraction of an α-proton of 2-cyclohexenone by LDA followed by treatment with phenylselenyl chloride which gave the corresponding phenol upon oxidation.This new methodology was applied in the conversion of 19-Nortestosterone to β-Estradiol.
- Al-Hassan, Mohammed I.
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p. 453 - 462
(2007/10/02)
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- SELECTIVE AROMATISATION OF CYCLOHEXENONE
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Selective aromatisation of cyclohexenone was achieved via abstraction of an α-proton of 2-cyclohexenone by LDA followed by treatment with phenylselenenyl chloride which gave the corresponding phenol upon oxidation.
- Al-Hassan, Mohammed I.
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p. 187 - 188
(2007/10/02)
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- FACILE SELECTIVE AMINOLYSIS OF PHENOLIC BENZOATES WITH 1-BUTANAMINE IN BENZENE
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1-Butanamine in benzene at room temperature effects selective aminolysis of phenolic benzoates without affecting aliphatic benzoates
- Bell, Kevin H.
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p. 2263 - 2264
(2007/10/02)
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- FLASH VACUUM THERMOLYSIS OF SPIROCYCLOHEXADIENONES
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In an attempt to prepare short-bridged hydroxymetacyclophanes 1b-d, the spirocyclohexadienones 2b-d were pyrolyzed by flash vacuum thermolysis (FVT).Instead of 1b-d,variable amounts of 4-(5-hexenyl)phenol (4b) , β-hydroxybenzocycloalkenes (5b-d) and 4-(trans-1-alkenyl)phenols (6c-d) were obtained.The formation of these products is explained by invoking cleavage of a spiro bond in 2 under formation of the intermediate diradical 3 which, depending on the length of the aliphatic chain and on the temperature, has several pathways open for isomerization to spin-paired products.
- Jenneskens, Leonardus W.,Wolf, Willem H. De,Bickelhaupt, Friedrich
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p. 3779 - 3784
(2007/10/02)
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- Inverse Electron Demand Diels-Alder Reactions of 3-Carbomethoxy-2-pyrones. Controlled Introduction of Oxygenated Aromatics: Benzene, Phenol, Catechol, Resorcinol, and Pyrogallol Annulation. Regiospecific Total Synthesis of Sendaverine and a Preparation of 6,7-Benzomorphans
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A full investigation of the preparation and Diels-Alder reactions of 3-carbomethoxy-2-pyrones is described.Methods for the preparation of a full range of oxygen-substituted aromatics: benzene, 1-, 2-, or 3-phenol, symmetrical or unsymmetrical o-catechol, resorcinol, and pyrogallol annulation from a common 3-carbomethoxy-2-pyrone intermediate are detailed.A regiospecific total synthesis of sendaverine, a 2-benzyltetrahydroisoquinoline possessing a selectively protected, symmetrical o-catechol, and a preparation of 6,7-benzomorphans are described.
- Boger, Dale B.,Mullican, Michael D.
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p. 4033 - 4044
(2007/10/02)
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- Reactions of 3-(Phenylthio)-3-buten-2-one with Cycloalkanones. A New Approach to Fused Phenols
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Synthesis and properties of 3-(phenylthio)-3-buten-2-one (7) have been described.The butenone 7 reacted with lithium cycloalkanone enolates to give ketols 14 or diketones 15 in good yields, which were easily transformed into fused phenols 17 by the treatment with p-toluenesulfonic acid or sodium ethoxide, respectively.Oxidative elimination of the sulfenyl group of 14a afforded also 2-naphthol 17a.Tetrahydronaphthalene 23, a key intermediate of calamenene 1a and calamenenal 1b, was successfully synthesized by this approach by starting from l-carvone (19).Bicyclooctanone 25 was obtained in the reaction of 7 with kinetic enolate of 2-cyclohexen-1-one in 84percent yield.
- Takaki, Ken,Okada, Michikazu,Yamada, Michio,Negoro, Kenji
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p. 1200 - 1205
(2007/10/02)
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- PROPELLANES-LIII THE -ENE REACTION OF OLEFINIC PROPELLANES WITH SINGLET OXYGEN
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The -ene reactions of propellanes containing an anhydride ring or a methylimide ring undergo secondary orbital control.In attack by 1O2 only the syn-products are obtained.In the corresponding lactone or ether steric hindrance plays a more important role in the direction of attack.
- Landheer, Iman,Ginsburg, David
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p. 143 - 150
(2007/10/02)
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- Annelation Reactions of 3-Phenylthiobut-3-en-2-one. A New Method of Constructing Fused Phenols
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Reactions of 3-phenylthiobut-3-en-2-one with enolate anions of cyclohexanone and cyclopentanone gave good yields of 8a-hydroxy-3-phenylthio-2-decalone and 3a-hydroxy-6-phenylthiohexahydroindan-5-one which were readily converted into 5,6,7,8-tetrahydro-2-naphthol and indan-5-ol, respectively, on exposure to toluene-p-sulphonic acid: a similar reaction of the enolate of cycloheptanone and subsequent treatment with sodium ethoxide gave 2-hydroxy-5,6,7,8-tetrahydrobenzocycloheptene.
- Takaki, Ken,Okada, Michikazu,Yamada, Michio,Negoro, Kenji
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p. 1183 - 1184
(2007/10/02)
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- The Synthesis of 4-Methylcyclohexa-2,5-dienones from Phenols
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4-Alkyl phenols have been converted by a known sequence into 2-aryloxyisobutyric acids and thence, by bromination at the 4-position of the aromatic ring with concomitant intramolecular lactone formation, into masked 4-alkyl-4-bromocyclohexa-2,5-dienones.Reaction with lithium dimethylcuprate, as a model for other lithium dialkylcuprates, replaces the bromine by a methyl group.Hydrolytic demasking gives 4-alkyl-4-methylcyclohexa-2,5-dienones.The method should allow the general synthesis of 4-alkylated cyclohexa-2,5-dienones from phenols via a nucleophilic alkylation step.This contrasts with an existing route which uses electrophilic alkylation of phenols or phenoxide ions by a restricted range of reactive alkylating agents.
- Islam, M. Majharul,Waring, Anthony J.
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p. 768 - 783
(2007/10/02)
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- Method for the production of 6-hydroxy-1,2,3,4-tetrahydronaphthalene
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There is described a process for the production of 6-hydroxy-1,2,3,4-tetrahydronaphthalene of formula I, STR1 which comprises treatment of beta naphthol with an absorbant, removal of the absorbant and selective hydrogenation of the resulting beta naphthol, preferably in a solvent which is inert under the reaction conditions. There is also described a process for the production of a compound of formula I using a rhodium catalyst.
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