- Monoallylation and benzylation of dicarbonyl compounds with alcohols catalysed by a cationic cobalt(iii) compound
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Monoallylation and monoalkylation of diketones and β-keto esters with allylic and benzylic alcohols catalysed by [Cp*Co(CH3CN)3][SbF6]2(I) are reported. The method does not require any additive and affords regioselective products. The mechanistic investigations were done byin situ1H NMR spectroscopy as well as control experiments. It has been shown that reactions proceedviaη3-allyl complex formation or ally ether intermediate. The alkylation takes placeviaonly ether intermediate. The resulting allylated and alkylated products have been used for the synthesis of eleven new trisubstituted pyrazoles and one pyrazolone.
- Chandra Sau, Mohan,Mandal, Smita,Bhattacharjee, Manish
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p. 9235 - 9245
(2021/03/16)
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- 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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- Intra- and intermolecular alkylation of N, O-acetals and π-activated alcohols catalyzed by in situ generated acid
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Intramolecular and intermolecular alkylations of carbocation precursors of limited ionization ability, principally N,O-acetals, without the use of an exogenous reagent have been developed. The reactions are carried out in 1,1,2,2-tetrachloroethane (TCE) a
- Hamon, Melanie,Dickinson, Niall,Devineau, Alice,Bolien, David,Tranchant, Marie-Jose,Taillier, Catherine,Jabin, Ivan,Harrowven, David C.,Whitby, Richard J.,Ganesan,Dalla, Vincent
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p. 1900 - 1912
(2014/04/03)
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- Yb(OTf)3-promoted effective benzylation and allylation with N-tosyl amino group as a stable leaving group
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A simple, inexpensive, environmentally friendly, and highly efficient benzylation and allylation of 1,3-dicarbonyl compounds with sulfonamides in the presence of Yb(OTf)3 is described. Yb(OTf)3 was proved to be a good catalyst for the cleavage of sp3 carbon-nitrogen bond. Various 1,3-dicarbonyl compounds can couple with a broad range of tosyl-activated benzylic and allylic amines to give diversely functionalized products in good to excellent yields.
- Liu, Jinqian,Wang, Limin,Zheng, Xingzhou,Wang, Aili,Zhu, Mengyun,Yu, Jianjun,Shen, Qiang
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supporting information; experimental part
p. 1843 - 1846
(2012/04/23)
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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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- Magnesium bistrifluoromethanesulfonimide as an efficient catalyst for the hydroalkylation of aromatic olefins with 1,3-diketones under solvent-free conditions
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An efficient magnesium bistrifluoromethanesulfonimide [Mg(NTf 2)2] catalyzed hydroalkylation of aromatic olefins with 1,3-diketones under solvent-free conditions has been developed. The reactions proceed smoothly to give the desired products in good yields in short reaction times.
- Wang, Hong She,Zhao, Wei Xing
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experimental part
p. 911 - 914
(2012/01/07)
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- Fe(ClO4)3·×H2O-Catalyzed direct C-C bond forming reactions between secondary benzylic alcohols with different types of nucleophiles
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Fe(ClO4)3·×H2O as a highly effective catalyst for benzylation of 1,3-dikones, β-ketoesters, 1,3-diesters, electron-rich arenes and heteroarenes and 4-hydroxycoumarin with various benzylic alcohols is described. The usefulness of this procedure is shown by a synthesis of bis-symmetrical triarylmethanes and one step synthesis of an anti-coagulant compound 4-hydroxy-3-(1,2,3,4-tetrahydronaphthalen-1-yl)-2H-chromen-2-one (Coumatetralyl (B)). The advantages of this protocol are broad scope, mild conditions, use of inexpensive catalyst and simplicity of operation since water is the only side product.
- Thirupathi, Ponnaboina,Kim, Sung Soo
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experimental part
p. 2995 - 3003
(2010/06/14)
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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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- Efficient nucleophilic substitution of -aryl alcohols with 1,3-dicarbonyl compounds catalyzed by tin ion-exchanged montmorillonite
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Tin ion-exchanged montmorillonite demonstrated the high catalytic activity for the direct nucleophilic substitution of a hydroxyl group in -aryl alcohols with various 1,3-dicarbonyl compounds including less acidic 1,3-diesters in crude solvents to afford
- Wang, Jiacheng,Masui, Yoichi,Onaka, Makoto
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experimental part
p. 2493 - 2497
(2010/12/18)
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- Synthesis of functionalized triarylmethanes by combination of FeCl3-catalyzed benzylations of acetylacetone with [3+3] cyclocondensations
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Functionalized triarylmethanes are prepared in two steps by FeCl3-catalyzed benzylation of acetylacetone to give 3-(diarylmethyl)pentane-2,4-diones and subsequent formal [3+3] cyclization of the latter with 1,3-bis(trimethylsilyloxy)-1,3-dienes
- Khera, Rasheed Ahmad,Ullah, Ihsan,Ahmad, Rasheed,Riahi, Abdolmajid,Hung, Nguyen Thai,Sher, Muhammad,Villinger, Alexander,Fischer, Christine,Langer, Peter
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experimental part
p. 1643 - 1652
(2010/04/04)
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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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- Iodine as a versatile catalyst for the hydroalkylation of vinyl arenes with 1,3-diketones
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The vinyl arenes undergo smooth hydroalkylation with 1,3-diketones in the presence of 10 mol % of iodine to afford phenethyl diketones and ketoesters in good yields in short reaction times. The use of inexpensive and readily available molecular iodine makes this method quite simple, more convenient and practical.
- Yadav,Reddy, B.V. Subba,Rao, T. Srinivasa,Bhavani,Raju
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supporting information; experimental part
p. 2622 - 2624
(2010/06/14)
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- An efficient iodine-catalyzed benzylation reaction of 1,3-dicarbonyl compounds
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Under mild conditions, iodine promotes the direct alkylation of 1,3-dicarbonyl compounds with benzylic alcohols or benzylic acetates. Georg Thieme Verlag Stuttgart.
- Li, Zhongxian,Duan, Zheng,Wang, Huaiqiu,Tian, Rongqiang,Zhu, Qianrui,Wu, Yangjie
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scheme or table
p. 2535 - 2539
(2009/05/07)
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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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- 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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- 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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- 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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