- Monoallylation and benzylation of dicarbonyl compounds with alcohols catalysed by a cationic cobalt(iii) compound
-
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
-
p. 9235 - 9245
(2021/03/16)
-
- Graphene oxide catalyzed ketone α-alkylation with alkenes: Enhancement of graphene oxide activity by hydrogen bonding
-
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
-
supporting information
p. 5379 - 5382
(2019/05/10)
-
- Base-free benzylation of 1,3-dicarbonyl compounds using sulfamic acid supported on silica by linker: a combined experimental and theoretical approach
-
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)
-
- Solvent-free alkylation of 1,3-dicarbonyl compounds with benzylic, propargylic and allylic alcohols catalyzed by La(NO3)3·6H2O
-
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)
-
- Synthesis and structure of an air-stable bis(isopropylcyclopentadienyl) zirconium perfluorooctanesulfonate and its catalyzed benzylation of 1,3-dicarbonyl derivatives with alcohols
-
An air-stable uninuclear complex of bis(isopropylcyclopentadienyl) zirconium perfluorooctane sulfonate (1a·H2O·3THF) was successfully synthesized by the reaction of (i-PrCp)2ZrCl2 with C17SO3Ag. The c
- Zhang, Xiaohong,Qiu, Renhua,Zhou, Congcong,Yu, Jingxing,Li, Ningbo,Yin, Shuangfeng,Xu, Xinhua
-
p. 1011 - 1017
(2015/01/30)
-
- Carbon-supported iron-ionic liquid: An efficient and recyclable catalyst for benzylation of 1,3-dicarbonyl compounds with alcohols
-
The effect of the addition of ILs with non-coordinating anions on the iron-catalyzed benzylation of 1,3-dicarbonyl compounds with alcohols under solvent free conditions has been evaluated. Among them, the presence of those containing the bistriflimide anion was found to be crucial for selectivity towards the benzylated product in a homogenous reaction. Therefore, the catalytic activity of Fe(OTf)3-N4111NTf2 combination supported on carbon materials with different textural and chemical surface properties has been studied. In the heterogeneous phase, reaction selectivity was also enhanced by the addition of the IL. However, substantial differences between the activities of different Fe-IL/carbon material catalytic systems were observed, indicating the influence of carbon support properties. With regards to selectivity, the best results were obtained using carbon supports with low microporosity. Moreover, the presence of oxygen functional groups on the carbon surface improved catalyst recycling. the Partner Organisations 2014.
- Moriel,Garcia
-
supporting information
p. 4306 - 4311
(2014/10/16)
-
- Fe(HSO4)3 : An efficient, heterogeneous and reusable catalyst for C-alkylation of β-dicarbonyl compounds
-
Fe(HSO4)3(FHS) was used as an efficient catalyst for the heterogeneous addition of a series of benzylic and allylic alcohols to various β-dicarbonyl compounds, which afforded moderate to excellent yields of C-alkylated products in 1,2-dichloroethane. In comparison with the previous methods, the present research surprisingly exhibited higher reaction yields without formation of any by-products which could be formed by self-condensation of alcohols. Moreover, the catalyst can be readily recovered and reused up to five times with almost maintained reactivity and yields.
- Khafajeh, Samaneh,Akhlaghinia, Batool,Rezazadeh, Soodabeh,Eshghi, Hossein
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p. 1903 - 1912
(2015/02/05)
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- The efficiency of the metal catalysts in the nucleophilic substitution of alcohols is dependent on the nucleophile and not on the electrophile
-
In this study, we investigate the effect of the electrophiles and the nucleophiles for eight catalysts in the catalytic SN1 type substitution of alcohols with different degree of activation by sulfur-, carbon-, oxygen-, and nitrogen-centered nucleophiles. The catalysts do not show any general variance in efficiency or selectivity with respect to the alcohols and follow the trend of alcohol reactivity. However, when it comes to the nucleophile, the eight catalysts show general and specific variances in the efficiency and selectivity to perform the desired substitution. Interestingly, the selectivity of the alcohols to produce the desired substitution products was found to be independent of the electrophilicity of the generated carbocations but highly dependent on the ease of formation of the cation. Catalysts based on iron(III), bismuth(III), and gold(III) show higher conversions for S-, C-, and N-centered nucleophiles, and BiIII was the most efficient catalyst in all combinations. Catalysts based on rhenium(I) or rhenium(VII), palladium(II), and lanthanum(III) were the most efficient in performing the nucleophilic substitution on the various alcohols with the O-centered nucleophiles. These catalysts generate the symmetrical ether as a by-product from the reactions of S-, C-, and N-centered nucleophiles as well, resulting in lower chemoselectivity. Who's the boss? In a comprehensive study of catalytic S N1 type direct substitution of alcohols, the catalysts do not show any general variance in efficiency or selectivity with respect to the alcohols but are highly variable with respect to the nucleophiles. The reactivity of the alcohols is independent of the electrophilicity of the generated carbocations but highly dependent on the ease of formation of the cation.
- Biswas, Srijit,Samec, Joseph S. M.
-
supporting information
p. 974 - 981
(2013/08/25)
-
- Yb(OTf)3-promoted effective benzylation and allylation with N-tosyl amino group as a stable leaving group
-
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)
-
- Ruthenium salophen triflate: A reusable catalyst for alkylation of 1,3-dicarbonyl compounds
-
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)
-
- Different products in the reaction of the alcohols with cyclic and acyclic 1,3-dicarbonyl compounds: K5CoW12O40 as an electron transfer nano catalyst
-
K5CoW12O40 was used as a highly effective catalyst for the benzylation of 1,3-dicarbonyl compounds. β-Keto enol ethers were obtained when cyclic 1,3-dicarbonyl compounds used in this conditions instead of linear ones. The present methodology offers a practical, simple, mild, environmentally friendly, and time-saving method for etherification. Very low loading of catalyst, ease of workup, ease of handling, and reusability of catalyst are other advantages of this catalyst.
- Rafiee, Ezzat,Kahrizi, Masoud,Joshaghani, Mohammad
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p. 1363 - 1366
(2013/02/22)
-
- Direct carbon-carbon bond formation from alcohols and active methylenes using NaHSO4/SiO2
-
A simple and efficient procedure for carbon-carbon bond formation has been developed starting from alcohols and active methylene-containing compounds using silica gel supported sodium hydrogen sulfate (NaHSO4/SiO 2) under mild conditions. NaHSO4/SiO2 can be reused without loss of catalytic activity at least ten times. Georg Thieme Verlag Stuttgart · New York.
- Aoyama, Tadashi,Miyota, Saki,Takido, Toshio,Kodomari, Mitsuo
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experimental part
p. 2971 - 2976
(2012/01/04)
-
- Magnesium bistrifluoromethanesulfonimide as an efficient catalyst for the hydroalkylation of aromatic olefins with 1,3-diketones under solvent-free conditions
-
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
-
experimental part
p. 911 - 914
(2012/01/07)
-
- FeCl3-catalyzed addition of nitrogen and 1,3-dicarbonyl nucleophiles to olefins
-
A direct intermolecular addition of nitrogen and 1,3-dicarbonyl nucleophiles to stabilized double bonds (styrenes, 1,3-dienes, enol-ethers, sugars.) in the presence of green and inexpensive FeCl3 catalyst is described.
- Zotto, Christophe Dal,Michaux, Julien,Zarate-Ruiz, Araceli,Gayon, Eric,Virieux, David,Campagne, Jean-Marc,Terrasson, Vincent,Pieters, Grégory,Gaucher, Anne,Prim, Damien
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experimental part
p. 296 - 304
(2011/02/17)
-
- Amberlyst-15 in ionic liquid: an efficient and recyclable reagent for the benzylation and hydroalkylation of β-dicarbonyl compounds
-
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)
-
- 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
-
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
-
experimental part
p. 4898 - 4903
(2010/10/02)
-
- Perchloric acid catalyzed homogeneous and heterogeneous addition of β-dicarbonyl compounds to alcohols and alkenes and investigation of the mechanism
-
(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
-
experimental part
p. 5017 - 5030
(2010/10/04)
-
- Synthesis of functionalized triarylmethanes by combination of FeCl3-catalyzed benzylations of acetylacetone with [3+3] cyclocondensations
-
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
-
experimental part
p. 1643 - 1652
(2010/04/04)
-
- Efficient nucleophilic substitution of -aryl alcohols with 1,3-dicarbonyl compounds catalyzed by tin ion-exchanged montmorillonite
-
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
-
experimental part
p. 2493 - 2497
(2010/12/18)
-
- Triflic acid adsorbed on silica gel as an efficient and recyclable catalyst for the addition of β-dicarbonyl compounds to alcohols and alkenes
-
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
-
supporting information; experimental part
p. 1049 - 1055
(2010/08/04)
-
- Fe(ClO4)3·×H2O-Catalyzed direct C-C bond forming reactions between secondary benzylic alcohols with different types of nucleophiles
-
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
-
experimental part
p. 2995 - 3003
(2010/06/14)
-
- Benzylation of β-dicarbonyl compounds and 4-hydroxycoumarin using TMSOTf catalyst: A simple, mild, and efficient method
-
The direct benzylation of 1,3-dicarbonyl compounds and 4-hydroxycoumarin with a wide variety of benzylic alcohols was achieved using trimethylsilyl trifluoromethanesulfonate as an efficient catalyst. The reaction proceeded under very mild conditions at ro
- Theerthagiri, Palani,Lalitha, Appaswami
-
supporting information; experimental part
p. 5454 - 5458
(2010/11/02)
-
- Iodine as a versatile catalyst for the hydroalkylation of vinyl arenes with 1,3-diketones
-
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
-
supporting information; experimental part
p. 2622 - 2624
(2010/06/14)
-
- Efficient and general continuous-flow hydroarylation and hydroalkylation of styrenes
-
A simple and efficient continuous-flow hydroarylation of arenes and heteroarenes using various styrenes in conjunction with a heterogeneous catalyst has been developed. Additionally, this method has been successfully extended to the hydroalkylation of styrenes by employing 1,3-dicarbonyl compounds as the nucleophile. Multigram quantities of diarylmethanes have been prepared using this new flow method. Copyright
- Rueping, Magnus,Bootwicha, Teerawut,Sugiono, Erli
-
experimental part
p. 2961 - 2965
(2011/02/22)
-
- Br?nsted acid ionic liquid-catalyzed direct benzylation, allylation and propargylation of 1,3-dicarbonyl compounds with alcohols as well as one-pot synthesis of 4H-chromenes
-
Recyclable ionic Br?nsted acid was prepared in nearly quantitative yield by reacting 1-butylimidazole with an equimolar amount of 1,3-propanesultone, followed by treatment with an equimolar amount of trifluoromethanesulfonic acid. The ionic Br?nsted acid-catalyzed direct benzylation, allylation and propargylation of 1,3-dicarbonyl compounds with various alcohols in ionic liquid [N-ethyl-N-methyl imidazolium trifluoromethanesulfonate (EMIOTf)], at 100 °C for 3 h proceeded smoothly to give the corresponding products in good to excellent yields without the use of any hazardous or volatile solvents and without any by-product such as salts. Furthermore, tandem benzylation-cyclization-dehydration of 1,3-dicarbonyl compounds to give functionalized 4H-chromenes was also achieved in this catalytic reaction.
- Funabiki, Kazumasa,Komeda, Takuya,Kubota, Yasuhiro,Matsui, Masaki
-
experimental part
p. 7457 - 7463
(2009/12/06)
-
- Selective benzylic and allylic alkylation of protic nucleophiles with sulfonamides through double Lewis acid catalyzed cleavage of sp3 carbon-nitrogen bonds
-
The acid-catalyzed benzylic and allylic alkylation of protic nucleophiles is fundamentally important for the formation of carbon-carbon and carbon-heteroatom bonds, and it is a formidable challenge for benzylic and allylic amine derivatives to be used as the alkylating agents. Herein we report a highly efficient benzylic and allylic alkylation of protic carbon and sulfur nucleophiles with sulfonamides through double Lewis acid catalyzed cleavage of sp3 carbon-nitrogen bonds at room temperature. In the presence of a catalytic amount of inexpensive ZnCl2-TMSCl (TMSCl: chlorotrimethylsilane), 1,3-diketones, β-keto esters, β-keto amides, malononitrile, aromatic compounds, thiols, and thioacetic acid can couple with a broad range of tosylactivated benzylic and allylic amines to give diversely functionalized products in good to excellent yields and with high regioselectivity. Furthermore, the cross-coupling reaction of 1,3-dicarbonyl compounds with benzylic propargylic amine derivatives has been successfully applied to the one-step synthesis of polysubstituted furans and benzofurans.
- Liu, Cong-Rong,Li, Man-Bo,Yang, Cui-Feng,Tian, Shi-Kai
-
experimental part
p. 793 - 797
(2009/09/29)
-
- Synthesis of functionalized triarylmethanes based on a 'FeCl3-catalyzed benzylation/[3+3] cyclocondensation' strategy
-
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
- Ahmad, Rasheed,Riahi, Abdolmajid,Langer, Peter
-
experimental part
p. 1490 - 1492
(2009/06/18)
-
- Simple and efficient metal-free hydroarylation and hydroalkylation using strongly acidic ion-exchange resin
-
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
-
experimental part
p. 42 - 43
(2009/12/02)
-
- Copper-catalyzed oxidative coupling of benzylic C-H bonds with 1,3-dicarbonyl compounds
-
(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.
-
p. 7822 - 7825
(2008/12/22)
-
- An efficient iodine-catalyzed benzylation reaction of 1,3-dicarbonyl compounds
-
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
-
scheme or table
p. 2535 - 2539
(2009/05/07)
-
- Phosphotungstic acid catalyzed direct benzylation of β-dicarbonyl compounds
-
12-Phosphotungstic acid was used as an efficient, ecofriendly, and air- and moisture-stable catalyst to promote the direct substitution of the hydroxy group of benzylic and allylic alcohols with various β-dicarbonyl compounds. This powerful protocol for c
- Wang, Guan-Wu,Shen, Ye-Bing,Wu, Xue-Liang
-
experimental part
p. 4999 - 5004
(2009/05/26)
-
- Microwave-irradiated transition-metal catalysis: Rapid and efficient dehydrative carbon-carbon coupling of alcohols with active methylenes
-
A rapid and highly productive synthetic microwave-irradiation protocol for transition-metal-catalyzed carbon-carbon coupling of a wide range of benzylic/allylic alcohols with β-diones, β-keto esters, and dialkyl malonates is reported. In a representative
- Babu, Srinivasarao Arulananda,Yasuda, Makoto,Tsukahara, Yasunori,Yamauchi, Tomohisa,Wada, Yuji,Baba, Akio
-
p. 1717 - 1724
(2008/12/22)
-
- Solvent-free hydroalkylation of olefins with 1,3-diketones catalyzed by phosphotungstic acid
-
An efficient and convenient method for the direct hydroalkylation of styrene and norborene with 1,3-diketones has been developed by using 12-phosphotungstic acid as an eco-friendly, and air- and moisture-tolerable catalyst. Reactions proceeded without any solvent, providing a clean access to alkylated 1,3-diketones.
- Wang, Guan-Wu,Shen, Ye-Bing,Wu, Xue-Liang,Wang, Lei
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p. 5090 - 5093
(2008/12/21)
-
- Efficient copper(II)-catalyzed addition of activated methylene compounds to alkenes
-
(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
-
p. 5647 - 5650
(2008/12/21)
-
- Bronsted acid-catalyzed benzylation of 1,3-dicarbonyl derivatives
-
The direct alkylation of 1,3-dicarbonyl compounds with benzylic alcohols is shown to be efficiently catalyzed by simple Bronsted acids such as triflic acid (TfOH) and p-toluenesulfonic acid (PTS) to give rise to monoalkylated dicarbonyl derivatives in high yields. In the absence of the nucleophile, substituted alkenes, generated through a formal dimerization reaction, are obtained. The reactions are carried out in air using undried solvents, with water being the only side product of the process.
- Sanz, Roberto,Miguel, Delia,Martinez, Alberto,Alvarez-Gutierrez, Julia M.,Rodriguez, Felix
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p. 2027 - 2030
(2008/02/02)
-
- A general and efficient iron-catalyzed benzylation of 1,3-dicarbonyl compounds
-
Various CH-acidic 1,3-dicarbonyl compounds and methyl 3-acetamidobut-2- enoate react with benzylic alcohols to give the corresponding 2-benzylated products in good to excellent yield. Typically, reactions proceed under mild conditions (50-80°C; air) in the presence of catalytic amounts of inexpensive iron chloride hexahydrate. The benzylation of 4-hydroxycoumarin gives the pharmaceutically interesting 4-hydroxy-3-(1-phenylethyl)-2H-chromen-2- ones. As an example the anticoagulant Phenprocoumon is prepared in one step from commercially available substrates in 94 % yield.
- Kischel, Jette,Mertins, Kristin,Michalik, Dirk,Zapf, Alexander,Beller, Matthias
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p. 865 - 870
(2008/03/18)
-
- A simple and efficient FeCl3-catalyzed direct alkylation of active methylene compounds with benzylic and allylic alcohols under mild conditions
-
A highly efficient FeCl3-catalyzed alkylation of various active methylene compounds with various benzylic or allylic alcohols under mild conditions has been developed. The reaction was carried out in the presence of a catalytic amount of anhydr
- Jana, Umasish,Biswas, Srijit,Maiti, Sukhendu
-
p. 4065 - 4069
(2008/02/03)
-
- An efficient Yb(OTf)3 catalyzed alkylation of 1,3-dicarbonyl compounds using alcohols as substrates
-
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
-
p. 3969 - 3973
(2008/02/04)
-
- Efficient metal-catalyzed direct benzylation and allylic alkylation of 2,4-pentanediones
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(Chemical Equation Presented) A highly effective metal-catalyzed benzylation and allylic alkylation of 2,4-pentanediones has been developed. This new bismuth-catalyzed direct carbon-carbon bond forming reaction provides the corresponding monoalkylated dicarbonyl compounds in high yields after short reaction times using the lowest amounts of catalyst (1 mol %) and the free alcohol. In addition, a new route to substituted indenes is presented.
- Rueping, Magnus,Nachtsheim, Boris J.,Kuenkel, Alexander
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p. 825 - 828
(2007/10/03)
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- Nucleophilic substitution reactions of alcohols with use of montmorillonite catalysts as solid Bronsted acids
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(Chemical Equation Presented) We have developed an environmentally benign synthetic approach to nucleophilic substitution reactions of alcohols that minimizes or eliminates the formation of byproducts, resulting in a highly atom-efficient chemical process. Proton- and metal-exchanged montmorillonites (H- and Mn+-mont) were prepared easily by treating Na +-mont with an aqueous solution of hydrogen chloride or metal salt, respectively. The H-mont possessed outstanding catalytic activity for nucleophilic substitution reactions of a variety of alcohols with anilines, because the unique acidity of the H-mont catalyst effectively prevents the neutralization by the basic anilines. In addition, amides, indoles, 1,3-dicarbonyl compounds, and allylsilane act as nucleophiles for the H-mont-catalyzed substitutions of alcohols, which allowed efficient formation of various C-N and C-C bonds. The solid H-mont was reusable without any appreciable loss in its catalytic activity and selectivity. Especially, an Al3+-mont showed high catalytic activity for the α-benzylation of 1,3-dicarbonyl compounds with primary alcohols due to cooperative catalysis between a protonic acid site and a Lewis acidic Al3+ species in its interlayer spaces.
- Motokura, Ken,Nakagiri, Nobuaki,Mizugaki, Tomoo,Ebitani, Kohki,Kaneda, Kiyotomi
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p. 6006 - 6015
(2008/02/10)
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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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- 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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- 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 metal-catalyzed hydroalkylation
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An efficient metal-catalyzed hydroalkylation of various styrenes, norbornene, and cyclohexadiene with 1,3-dicarbonyl compounds has been developed. This new bismuth-catalyzed C-H functionalization provides the corresponding alkylated pentanediones in good to excellent isolated yields after short reaction times. Georg Thieme Verlag Stuttgart.
- Rueping, Magnus,Nachtsheim, Boris J.,Kuenkel, Alexander
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p. 1391 - 1394
(2008/02/13)
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- Bronsted acid-catalyzed nucleophilic substitution of alcohols
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Simple Bronsted acids such as p-toluene-sulfonic acid monohydrate (PTS) or polymer-bound p-toluenesulfonic acid efficiently catalyze the direct nucleophilic substitution of the hydroxy group of allylic and benzylic alcohols with a large variety of carbon- and heteroatom-centered nucleophiles. Reaction conditions are mild, the process is conducted under an atmosphere of air without the need for dried solvents, and water is the only side product of the reaction.
- Sanz, Roberto,Martinez, Alberto,Miguel, Delia,Alvarez-Gutierrez, Julia M.,Rodriguez, Felix
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p. 1841 - 1845
(2007/10/03)
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- Bronsted acid mediated heterogeneous addition reaction of 1,3-dicarbonyl compounds to alkenes and alcohols
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(Chemical Equation Presented) The unique acidity of a proton-exchanged montmorillonite catalyst (H-mont) was exploited in the nucleophilic addition of 1,3-dicarbonyl compounds to simple alkenes (see scheme). The benzylation and allylation of 1,3-dicarbony
- Motokura, Ken,Fujita, Noriaki,Mori, Kohsuke,Mizugaki, Tomoo,Ebitani, Kohki,Kaneda, Kiyotomi
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p. 2605 - 2609
(2007/10/03)
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- Direct carbon-carbon bond formation from alcohols and active methylenes, alkoxyketones, or indoles catalyzed by indium trichloride
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(Chemical Equation Presented) The unsalted variety: The direct coupling reaction of alcohols with active methylenes, alkoxyketones, or indoles catalyzed by InCl3 proceeds without the formation of metal salts (see scheme). As H2O is the only by-product of this system, the alkylated products are easily isolated in pure form, and the reaction is suitable for large-scale synthesis.
- Yasuda, Makoto,Somyo, Toshio,Baba, Akio
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p. 793 - 796
(2007/10/03)
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- An effective bismuth-catalyzed benzylation of arenes and heteroarenes
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A highly efficient Bi(OTf)3-catalyzed benzylation of arenes and heteroarenes has been developed. The mild reaction conditions, high yields, operational simplicity and practicability, broad scope, and remarkably low catalyst loading render this environment friendly process an attractive approach to diarylmethane derivatives. The extension to an intramolecular variant of this procedure provides a valuable route to substituted fluorenes.
- Rueping, Magnus,Nachtsheim, Boris J.,Ieawsuwan, Winai
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p. 1033 - 1037
(2007/10/03)
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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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