- Graphene oxide catalyzed ketone α-alkylation with alkenes: Enhancement of graphene oxide activity by hydrogen bonding
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Direct α-alkylation of carbonyl compounds represents a fundamental bond forming transformation in organic synthesis. We report the first ketone-alkylation using olefins and alcohols as simple alkylating agents catalyzed by graphene oxide. Extensive studies of the graphene surface suggest a pathway involving dual activation of both coupling partners. Notably, we show that polar functional groups have a stabilizing effect on the GO surface, which results in a net enhancement of the catalytic activity. The method represents the first alkylation of carbonyl compounds using graphenes, which opens the door for the development of an array of protocols for ketone functionalization employing common carbonyl building blocks and readily available graphenes.
- Meng, Guangrong,Patel, Mehulkumar,Luo, Feixiang,Li, Qingdong,Flach, Carol,Mendelsohn, Richard,Garfunkel, Eric,He, Huixin,Szostak, Michal
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supporting information
p. 5379 - 5382
(2019/05/10)
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- Base-free benzylation of 1,3-dicarbonyl compounds using sulfamic acid supported on silica by linker: a combined experimental and theoretical approach
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Abstract: Sulfamic acid stabilized on the surface of silica by the n-propyl organic group linker which is named silica-bonded N-propylsulfamic acid was applied as an efficient heterogeneous catalyst with good recyclability and reusability for direct benzylation of 1,3-dicarbonyl compounds using secondary aromatic alcohols or styrenes as alkylating agents in high yields and short reaction times. All the reactions were carried out in nitromethane as solvent under an air atmosphere. The catalyst showed reusable feature by six times without a significant loss in its activity. Graphical abstract: [Figure not available: see fulltext.].
- Karimzadeh, Morteza,Saberi Asl, Hamed,Hashemi, Hajar,Saberi, Dariush,Niknam, Khodabakhsh
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p. 2237 - 2244
(2018/10/31)
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- Solvent-free alkylation of 1,3-dicarbonyl compounds with benzylic, propargylic and allylic alcohols catalyzed by La(NO3)3·6H2O
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An efficient and solvent free method for benzylation, propargylation and allylation of 1,3-dicarbonyl compounds with alcohols has been developed by using La(NO3)3·6H2O as water tolerable catalyst. The reaction was shown to proceed smoothly for various 1,3-dicarbonyl compounds with benzylic, propargylic and allylic alcohols including 1° allylic alcohols, without any solvent, providing a clean access to the desired products in short reaction times with good to excellent yields and high selectivity.
- Subramanyam, Madala,Rao, Koya Prabhakara,Varala, Ravi,Rao, Mandava V. Basaveswara
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p. 1155 - 1160
(2016/03/01)
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- Sulfuric acid catalyzed addition of β-dicarbonyl compounds to alcohols under conventional heating and microwave-assisted conditions
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The highly efficient direct addition of β-dicarbonyl compounds to secondary alcohols has been achieved using one of the cheapest acids, H 2SO4, as the catalyst. For a series of β-dicarbonyl compounds and various secondary alcohols, t
- Xia, Fei,Zhao, Zheng Le,Liu, Pei Nian
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supporting information; experimental part
p. 2828 - 2832
(2012/07/17)
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- Ruthenium salophen triflate: A reusable catalyst for alkylation of 1,3-dicarbonyl compounds
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Reaction of 1,3-dicarbonyl compounds with alcohols or olefins in the presence of catalytic amounts of electron-deficient [Ru(salophen)OTf] produced α-alkylated 1,3-dicarbonyls under solvent-free conditions. Different substituted benzylic alcohols were efficiently reacted with 2,4-pentanedione or 1,3-diphenyl-1,3-propanedione and their corresponding alkylated diones were obtained in good to excellent yield. On the other hand, substituted styrenes were also converted to their corresponding α-alkylated 1,3-dicarbonyls in good yields. The effect of reaction parameters such as solvent, amount of catalyst and axial substituent on the ruthenium salophen was also investigated. The catalyst was reusable several times without loss of its activity.
- Barati, Behjat,Moghadam, Majid,Rahmati, Abbas,Mirkhani, Valiollah,Tangestaninejad, Shahram,Mohammadpoor-Baltork, Iraj
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p. 122 - 126
(2013/01/15)
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- Highly efficient microwave-assisted substitution of β-dicarbonyl compounds with secondary alcohols using fluoroboric acid as the catalyst
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The microwave-assisted substitution of β-dicarbonyl compounds with secondary alcohols has been achieved efficiently, using very cheap fluoroboric acid (HBF4) as the catalyst. For various β-dicarbonyl compounds and a series of secondary alcohols
- Liu, Peinian,Xia, Fei,Ren, Yujie,Chen, Junqin
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p. 2075 - 2080
(2012/03/11)
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- Amberlyst-15 in ionic liquid: an efficient and recyclable reagent for the benzylation and hydroalkylation of β-dicarbonyl compounds
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Benzylation and hydroalkylation of 1,3-dicarbonyl compounds using Amberlyst-15 immobilized in ionic liquid [Bmim][PF6] as an efficient reusable reagent was studied. The reagent was compared with other solid acid reagents along with role of the ionic liquid. The effect of various reaction parameters like type of reagent, solvent, substrate molar ratio, reaction time, and temperature were studied. Present protocol is advantageous due to the ease in handling of reagent, simple work-up procedure, economical and environmentally benign process. The products were obtained in good to excellent yield and applicable to wide variety of substrates.
- Qureshi, Ziyauddin S.,Deshmukh, Krishna M.,Tambade, Pawan J.,Bhanage, Bhalchandra M.
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scheme or table
p. 724 - 729
(2010/04/05)
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- Perchloric acid catalyzed homogeneous and heterogeneous addition of β-dicarbonyl compounds to alcohols and alkenes and investigation of the mechanism
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(Figure presented) The direct addition of various β-dicarbonyl compounds to a series of secondary alcohols and alkenes has been achieved using 1 mol % perchloric acid (HClO4) as the catalyst. The HClO 4-catalyzed reactions could be conveniently conducted in commercial solvent and gave moderate to excellent yields. Moreover, the silica gel-supported HClO4 could also catalyze the heterogeneous addition for a series of substrates with similar or even higher yields in comparison with the homogeneous ones. The supported catalyst could be readily recovered and reused for four runs. Furthermore, the mechanism of the HClO4- catalyzed addition of the β-diketone to alcohol was investigated, and an SN1 mechanism was proved unambiguously for the first time through a series of experiments. The discrimination of catalytic abilities among different Bronsted acids was also rationalized by DFT calculations.
- Liu, Pei Nian,Dang, Li,Wang, Qing Wei,Zhao, Shu Lei,Xia, Fei,Ren, Yu Jie,Gong, Xue Qing,Chen, Jun Qin
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experimental part
p. 5017 - 5030
(2010/10/04)
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- Metal-free oxidative C-C bond formation of active methylenic sp3 C-H bonds with benzylic sp3 C-H and allylic sp3 C-H bonds mediated by DDQ
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An efficient and simple method for the oxidative coupling of benzylic and allylic sp3 C-H bonds with active methylenic sp3 C-H bonds under metal-free conditions was developed by employing 2,3-dichloro-5,6- dicyanobenzoquinone (DDQ) as an oxidant. The reaction was shown to proceed smoothly for various 1,3-dicarbonyl compounds with a range of benzylic and allylic substrates in good to excellent yields.
- Ramesh,Ramulu,Rajaram,Prabhakar,Venkateswarlu
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experimental part
p. 4898 - 4903
(2010/10/02)
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- Triflic acid adsorbed on silica gel as an efficient and recyclable catalyst for the addition of β-dicarbonyl compounds to alcohols and alkenes
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The silica gel supported triflic acid was readily prepared via simple absorption of TfOH onto chromatographic silica gel. This solid acid was applied as an efficient catalyst for the heterogeneous addition of various β-dicarbonyl compounds to a series of alcohols and alkenes, which afforded moderate to excellent yields under solvent-free conditions or in nitromethane. Moreover, this silica gel supported catalyst surprisingly exhibited higher reaction yields in comparison with the homogeneous catalyst and can be readily recovered and reused up to 6 times with almost maintained reactivity and yields.
- Liu, Pei Nian,Xia, Fei,Wang, Qing Wei,Ren, Yu Jie,Chen, Jun Qin
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supporting information; experimental part
p. 1049 - 1055
(2010/08/04)
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- Simple and efficient metal-free hydroarylation and hydroalkylation using strongly acidic ion-exchange resin
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Higly efficient hydroarylation and hydroalkylation of styrenes with various arenes and 1,3-dicarbonyl compounds respectively have been developed using Amberlyst-15 as a heterogeneous catalyst. The excellent yields, short reaction times, and high selectivity are the advantages of this method. The C-H functionalization has been achieved here under metal-free conditions. Copyright
- Das, Biswanath,Krishnaiah, Martha,Laxminarayana, Keetha,Damodar, Kongara,Kumar, D. Nandan
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experimental part
p. 42 - 43
(2009/12/02)
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- Efficient copper(II)-catalyzed addition of activated methylene compounds to alkenes
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(Chemical Equation Presented) Efficient regioselective addition of β-diketones to styrenes, norbornene, cyclic enol ether, and diene has been realized by means of copper(II) triflate as the catalyst. The solvent effect is prominent on the reactions, and the desired addition products were obtained in good to excellent yields only in dioxane or ionic liquid [bmim]PF6. The mechanism suggests that copper(II) triflate activates the enolic O-H bond of a β-diketone substrate to initiate the addition reaction.
- Li, Yu,Yu, Zhengkun,Wu, Sizhong
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p. 5647 - 5650
(2008/12/21)
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- Copper-catalyzed oxidative coupling of benzylic C-H bonds with 1,3-dicarbonyl compounds
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(Chemical Equation Presented) A copper-catalyzed oxidative coupling of benzylic C-H bonds with 1,3-dicarbonyl compounds is described. The reaction utilizes an inexpensive copper catalyst-oxidant system that is suitable for the coupling of a range of benzylic C-H bonds with various 1,3-dicarbonyl compounds. Kinetic isotope studies support a mechanism involving a benzylic hydrogen abstraction.
- Borduas, Nadine,Powell, David A.
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p. 7822 - 7825
(2008/12/22)
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- The lewis acidic ruthenium-complex-catalyzed addition of β-diketones to alcohols and styrenes is in fact brensted acid catalyzed
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The Perchlorate salt of the dicationic bipy-ruthenium complex cis-[Ru(6,6′-Cl2bipy)2(H2O)2] 2+ effectively catalyzes addition of β-diketones to secondary alcohols and styrenes to yield the α-alkylated β-diketones. In a catalytic addition reaction of acetylacetone to 1-phenylethanol, the κ2-acetylacetonate complex [Ru(6,6′-Cl 2bipy)2(κ2-acac)]ClO4 was isolated after the catalysis; this complex is readily synthesized by reacting cis-[Ru(6,6′-Cl2bipy)2-(H2O) 2] (ClO4)2 with acetylacetone. [Ru(6,6′-Cl2bipy)2(κ-acac)]ClO4 is unreactive toward 1-phenylethanol in the presence of HClO4; it also fails to catalyze the addition of acetylacetone to 1-phenylethanol. On the basis of these observations, it is proposed and confirmed by independent experiments that the catalytic addition of β-diketones to the secondary alcohols is in fact catalyzed by the Bronsted acid HClO4, which is generated by the reaction of cis-[Ru(6,6′-Cl2bipy)2(H 2O)2]-(ClO4)2 with the β-diketone.
- Liu, Pei Nian,Zhou, Zhong Yuan,Lau, Chak Po
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p. 8610 - 8619
(2008/04/01)
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- Indium(III)-catalyzed addition of 1,3-dicarbonyl compounds to alkenes
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A new InCl3-catalyzed addition reaction of 1,3-dicarbonyl compounds to various alkenes proceeded in good yields and can be carried out in air, which provided an easy and practical procedure for carbon-carbon bond formation. Georg Thieme Verlag Stuttgart.
- Yuan, Yu,Shi, Zhuangzhi
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p. 3219 - 3223
(2008/09/20)
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- FeCl3 catalyzed addition of activated methylenes to styrene derivatives under air
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An efficient addition of activated methylene to styrene derivatives catalyzed by cheap and environment-friendly FeCl3 was developed. The reaction can be carried out under 'open-flask' conditions in which no precautions were taken to exclude moisture and air.
- Duan, Zheng,Xuan, Xuejie,Wu, Yangjie
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p. 5157 - 5159
(2008/02/10)
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- An efficient Yb(OTf)3 catalyzed alkylation of 1,3-dicarbonyl compounds using alcohols as substrates
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A highly efficient and environmentally friendly method for catalytic benzylation/allylation of 1,3-dicarbonyl compounds with alcohols has been developed by using Yb(OTf)3 as a catalyst. The reactions proceed smoothly to give the desired products in moderate to excellent yields, mostly at room temperature. The catalyst can be recovered and reused at least six times without visible loss of catalytic activity for such reactions.
- Huang, Wen,Wang, Jialiang,Shen, Quansheng,Zhou, Xigeng
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p. 3969 - 3973
(2008/02/04)
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- Metal triflate-catalyzed cationic benzylation and allylation of 1,3-dicarbonyl compounds
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(Chemical Equation Presented) The rare earth metal and hafnium triflate-catalyzed secondary benzylation and allylation of 1,3-diketones, ketoesters, and ketoamides are described. The procedure was carried out under non-anhydrous conditions. Various 1-phenylethyl cations were generated from substituted 1-phenylethanols using 0.5 mol % of the metal triflates in CH 3NO2. The cations reacted with 1,3-diketones and ketoesters to give benzylated products in high yields. Following the GC analysis, the reaction conditions were easily optimized by the selection of catalysts based on the Lewis acidity of the triflates and reaction temperature. A tertiary-alkylated diketone and a corresponding ketoester were also benzylated to afford products with a quaternary carbon atom in 57-84% yield. The ketoamide reactions required stronger Lewis acids than those used in the diketone and ketoester reactions. The reactions of benzylic alcohols possessing various substituents on the aromatic ring and dibenzoylmethane (2b) as a diketone were examined in the presence of Hf(OTf)4. Electron-rich benzylic alcohols reacted with 2b in 86-96% yield, and electron-deficient alcohol gave the desired product in 79-65% yield. Despite possessing a strong electron-withdrawing group, the reaction of 1-(4-nitrophenyl)ethanol gave the corresponding product in 61% yield. It was also possible to use allylic alcohols directly for the allylation of diketone 2b. The catalyst can be recovered by water extraction and reused up to five times.
- Noji, Masahiro,Konno, Yosuke,Ishii, Keitaro
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p. 5161 - 5167
(2008/02/07)
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- Highly efficient, reversible addition of activated methylene compounds to styrene derivatives catalyzed by silver catalysts
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A highly efficient inter- and intramolecular addition of 1,3-diketone/β-ketoester to alkenes was developed by using silver catalysts. Silver triflate shows the highest catalytic activity. The reaction is reversible through the cleavage of a carbon-carbon bond by silver at an elevated temperature.
- Yao, Xiaoquan,Li, Chao-Jun
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p. 5752 - 5755
(2007/10/03)
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- Highly efficient addition of activated methylene compounds to alkenes catalyzed by gold and silver
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A highly efficient intermolecular addition of 1,3-diketones to alkenes catalyzed by AuCl3/AgOTf was developed. A mechanistic rationale for the reaction has been proposed via a α-C-H activation. Copyright
- Yao, Xiaoquan,Li, Chao-Jun
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p. 6884 - 6885
(2007/10/03)
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