- Selective Acetalization of ethylene glycol with methyl 2-napthyl ketone over solid acids: Efficacy of acidic clay supported Cs2.5H0.5PW12O40
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Catalytic conversion of biomass to value added products is relevant with regard to several industries. Biomass derived ethylene glycol has many applications. Acetalization is used to synthesize valuable chemicals and also occasionally to protect carbonyl
- Yadav, Ganapati D.,Katole, Suraj O.
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Read Online
- Experimental and Theoretical Study of the Effectiveness and Stability of Gold(I) Catalysts Used in the Synthesis of Cyclic Acetals
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Different [AuL]+ fragments (L = tertiary phosphines, ylides, or NHC carbene) have been tested under mild conditions as suitable catalysts for the transformation of terminal or internal alkynes into the corresponding cyclic acetals upon reaction
- Cordón, Jesús,López-De-Luzuriaga, José M.,Monge, Miguel
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Read Online
- Ni-catalyzed reductive decyanation of nitriles with ethanol as the reductant
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A nickel-catalyzed reductive decyanation of aromatic nitriles has been developed, in which the readily available and abundant ethanol was applied as the hydride donor. Various functional groups on the aromatic rings, such as alkoxyl, amino, imino and amide, were compatible in this catalytic protocol. Heteroaryl, benzylic and alkenyl nitriles were also tolerated. Mechanistic investigation indicated that ethanol provided hydride efficientlyviaβ-hydride elimination in this reductive decyanation.
- Wu, Ke,Ling, Yichen,Sun, Nan,Hu, Baoxiang,Shen, Zhenlu,Jin, Liqun,Hu, Xinquan
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supporting information
p. 2273 - 2276
(2021/03/09)
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- Green efficient synthesis of ketal under catalysis of ionic liquid TTPT
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The invention discloses a method for green efficient synthesis of ketal under catalysis of ionic liquid TTPT. The method comprises the following steps: adding TTPT and a water-carrying agent into a raw material I and a raw material II, and carrying out a heating reflux reaction for 110-150 minutes, wherein R1 and R2 in formulas I and II are independently selected from a group consisting of a methyl group, an ethyl group and a phenyl group, or R1 and R2 are connected and cyclized to form a 5-to-10-membered naphthenic base; and R3 is selected from H or-OH. Compared with the prior art, the catalytic yield of the TTPT is remarkably improved, a good catalytic effect is achieved, and experimental operation is easy and convenient.
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Paragraph 0044-0047
(2021/08/07)
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- Utilization of 1,3-Dioxolanes in the Synthesis of α-branched Alkyl and Aryl 9-[2-(Phosphonomethoxy)Ethyl]Purines and Study of the Influence of α-branched Substitution for Potential Biological Activity
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Syntheses of α-branched alkyl and aryl substituted 9-[2-(phosphonomethoxy)ethyl]purines from substituted 1,3-dioxolanes have been developed. Key synthetic precursors, α-substituted dialkyl [(2-hydroxyethoxy)methyl]phosphonates were prepared via Lewis acid mediated cleavage of 1,3-dioxolanes followed by reaction with dialkyl or trialkyl phosphites. The best preparative yields were achieved under conditions utilizing tin tetrachloride as Lewis acid and triisopropyl phosphite. Attachment of purine bases to dialkyl [(2-hydroxyethoxy)methyl]phosphonates was performed by Mitsunobu reaction. Final α-branched 9-[2-(phosphonomethoxy)ethyl]purines were tested for antiviral, cytostatic and antiparasitic activity, the latter one determined as inhibitory activity towards Plasmodium falciparum enzyme hypoxanthine-guanine-xanthine phosphoribosyltransfesase. In most cases biological activity was only marginal.
- Pomeisl, Karel,Pohl, Radek,Snoeck, Robert,Andrei, Graciela,Kre?merová, Marcela
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p. 119 - 156
(2019/01/04)
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- METHOD FOR PRODUCTION OF AROMATIC COMPOUND
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PROBLEM TO BE SOLVED: To solve such problems that the replacement of a nitro group with a hydrogen atom in production of an aromatic compound requires two-type reactions different from each other comprising reduction to an amino group and conversion of diazonium salt, and those procedures contain such problems that many processes are required and it takes time in production in view of convenience in aftertreatment of reaction and refining operation; and further, a careful handling is required regarding the diazonium salt because that salt is unstable depending on the type of compound and is an intermediate having sometimes the risk of explosion. SOLUTION: There is provided an aromatic compound production method characterized by including: reacting an aromatic nitro compound with a proton supply compound under the presence of a metal catalyst; and directly reducing the nitro group of the aromatic nitro compound to a hydrogen atom. SELECTED DRAWING: None COPYRIGHT: (C)2018,JPOandINPIT
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Paragraph 0054; 0063
(2018/10/16)
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- Reductive Denitration of Nitroarenes
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The Pd-catalyzed reductive denitration of nitroarenes has been achieved via a direct cleavage of the C-NO2 bonds. The catalytic conditions reported exhibit a broad substrate scope and good functional-group compatibility. Notably, the use of inexpensive propan-2-ol as a mild reductant suppresses the competitive formation of anilines, which are normally formed by other conventional reductions. Mechanistic studies have revealed that alcohols serve as efficient hydride donors in this reaction, possibly through β-hydride elimination from palladium alkoxides.
- Kashihara, Myuto,Yadav, M. Ramu,Nakao, Yoshiaki
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supporting information
p. 1655 - 1658
(2018/03/23)
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- 8-Hydroxy-2-methylquinoline-modified H4SiW12O40: A reusable heterogeneous catalyst for acetal/ketal formation
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A heteropoly acid based organic hybrid heterogeneous catalyst, HMQ-STW, was prepared by combining 8-hydroxy-2-methylquinoline (HMQ) with Keggin-structured H4SiW12O40 (STW). The catalyst was characterized via elemental analysis, X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermogravimetric analysis (TG) and potentiometric titration analysis. The catalytic performance of the catalyst was assessed in the ketalization of ketones with glycol or 1,2-propylene glycol. Various reaction parameters, such as the glycol to cyclohexanone molar ratio, catalyst dosage, reaction temperature and time, were systematically examined. HMQ-STW exhibited a relatively high yield of corresponding ketal, with 100% selectivity under the optimized reaction conditions. Moreover, catalytic recycling tests demonstrated that the heterogeneous catalyst exhibited high potential for reusability, and it was revealed that the organic modifier HMQ plays an important role in the formation of a heterogeneous system and the improvement of structural stability. These results indicated that the HMQ-STW catalyst is a promising new type of heterogeneous acid catalyst for the ketalization of ketones.
- Liu, Li-Jun,Luan, Qing-Jie,Lu, Jing,Lv, Dong-Mei,Duan, Wen-Zeng,Wang, Xu,Gong, Shu-Wen
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p. 26180 - 26187
(2018/08/04)
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- Synthesis of dioxolanes and oxazolidines by silica gel catalysis
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Abstract: Ethylene glycol condensed with carbonyl compounds in the presence of silica gel or alumina, without solvent and under pressure, affords 1,3-dioxolanes. 2-Amino-2-methylpropanol also condensed with carbonyl compounds in the presence of silica gel or an acid-activated clay, without solvent and under pressure, produces oxazolidines. To explain these results, we propose that the glycol and the aminopropanol react with Br?nsted (H+) and Lewis acid sites (Si and Al) located on the surface of the catalysts, leading to the products via various ionic intermediates.
- Rohand, Taoufik,Savary, Jér?me,Markó, István E.
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p. 1429 - 1436
(2018/06/25)
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- Ketalization of ketones to 1,3-dioxolanes and concurring self-aldolization catalyzed by an amorphous, hydrophilic SiO2-SO3H catalyst under microwave irradiation
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The amorphous, mesoporous SiO2-SO3H catalyst with a surface area of 115 m2 g-1 and 1.32 mmol H+ per g was very efficient for the protonation of ketones on a 10percent (m/m) basis, and the catalyst-bound intermediates can be trapped by polyalcohols to produce ketals in high yields or suffer aldol condensations within minutes under low-power microwave irradiation. The same catalyst can easily reverse the ketalization reaction. Printed in Brazil-
- Barbosa, Sandro L.,Ottone, Myrlene,De Almeida, Mainara T.,Lage, Guilherme L.C.,Almeida, Melina A.R.,Nelson, David Lee,Dos Santos, Wallans T.P.,Clososki, Giuliano C.,Lopes, Norberto P.,Klein, Stanlei I.,Zanatta, Lucas D.
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p. 1663 - 1671
(2018/06/29)
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- A fluorinated cobalt(III) porphyrin complex for hydroalkoxylation of alkynes
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A fluorinated cobalt(III) porphyrin complex [Co(TPFPP)-NTf2·2C2H5OH, where TPFPP=5,10,15,20-tetrakis(penta-fluorophenyl)porphyrin, Tf=CF3SO2] promotes hydroalkoxylation of alkynes to give acetals in good to excellent yields. The acetals can be directly functionalized with nucleophiles in a one-pot procedure.
- Ushimaru, Richiro,Nishimura, Takuho,Iwatsuki, Toshiki,Naka, Hiroshi
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p. 1000 - 1003
(2017/11/17)
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- Subsititue Material As Well As Production Process And Application
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The invention relates to a production process of a functionalized material containing acid groups and an application thereof. The material is used as a nonhomogenous catalyst, and can be used for removing organic and inorganic compounds in product streams, process streams and waste liquid, or can be used as a cation and anion exchanger, a metal chromatography material, a solid phase purifying or extracting material, a fixed biological moleculaar material, a solid phase sythesizing material and a chromatography material. The invention also relates to a novel sulfonic acid or hypophosphorous organic funtionalized silica gel and metal salts thereof.
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Paragraph 0106; 0107
(2017/08/28)
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- A bifunctional cerium phosphate catalyst for chemoselective acetalization
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Acid-base solid catalysts synthesized with structurally controlled uniform active sites can lead to unique catalysis. In this study, a CePO4 catalyst was synthesized using a hydrothermal method and found to exhibit high catalytic performance for the chemoselective acetalization of 5-hydroxymethylfurfural with alcohols, in sharp contrast to other homogeneous and heterogeneous acid and/or base catalysts. In the presence of CePO4, various combinations of carbonyl compounds and alcohols are efficiently converted into the corresponding acetal derivatives in good to excellent yields. Mechanistic studies show that CePO4 most likely acts as a bifunctional catalyst through the interaction of uniform Lewis acid and weak base sites with 5-hydroxymethylfurfural and alcohol molecules, respectively, which results in high catalytic performance.
- Kanai, Shunsuke,Nagahara, Ippei,Kita, Yusuke,Kamata, Keigo,Hara, Michikazu
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p. 3146 - 3153
(2017/04/04)
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- Stable yet reactive cationic gold catalysts with carbon based counterions
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L-Au-[TsC(CN)2] are new cationic gold catalysts with a carbon based counterion, which are widely applicable for gold catalyzed reactions. For reactions which need highly reactive gold catalysts, a Lewis acid co-catalyst can be added to increase
- Zeng, Xiaojun,Liu, Shiwen,Xu, Bo
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p. 77830 - 77833
(2018/06/22)
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- Cyclopentyl methyl ether-NH4X: A novel solvent/catalyst system for low impact acetalization reactions
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Cyclopentyl methyl ether, a low impact ether forming a positive azeotrope with water, was successfully employed as a solvent in the synthesis of 1,3-dioxanes and 1,3-dioxolanes carried out under Dean-Stark conditions by the acetalization of aliphatic and aromatic aldehydes or ketones, employing ammonium salts as environmentally friendly acidic catalysts.
- Azzena, Ugo,Carraro, Massimo,Mamuye, Ashenafi Damtew,Murgia, Irene,Pisano, Luisa,Zedde, Giuseppe
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supporting information
p. 3281 - 3284
(2015/06/25)
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- Highly efficient acetalization of carbonyl compounds catalyzed by anilin-aldehyde resin salts
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A mild procedures for the syntheses of ethylene acetals and dimethyl acetals from the corresponding aldehydes and ketones catalyzed by 1mol% of anilinealdehyde resin salts are described. This method is also useful for the synthesis of dimethyl acetals of diaryl ketones.
- Tanemura, Kiyoshi,Suzuki, Tsuneo
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supporting information
p. 797 - 799
(2015/06/22)
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- Selective acetalization of ethylene glycol with methyl 2-napthylketone over solid acids: Efficacy of acidic clay supported Cs2.5H0.5PW12O40
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Catalytic conversion of biomass to value added products is relevant with regard to several industries.Biomass derived ethylene glycol has many applications. Acetalization is used to synthesize valuablechemicals and also occasionally to protect carbonyl gr
- Yadav, Ganapati D.,Katole, Suraj O.
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p. 125 - 135
(2015/11/03)
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- Syntheses, structures, and catalytic activities of copper(I) complexes with the ligand 2(4,5-diphenyl-1H-imidazol-2-yl)pyridine
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Two copper(I) complexes of compositions [Cu(HL)I]2·EtOH (1) and [Cu(HL)3]I·MeOH (2) were synthesized via the reactions of HL [HL = 2(4,5-diphenyl-1H-imidazol-2-yl)pyridine] and CuI in EtOH and MeOH, respectively, under solvothermal conditions. The complexes were characterized by X-ray single crystal diffraction, IR spectroscopy, and elemental analysis. Compounds 1 and 2 are catalytically active towards ketalization reaction, giving various ketals under mild conditions. Copyright
- Yang, Hua,Liu, Yonglu,Hu, Dao-Dao
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p. 394 - 397
(2014/03/21)
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- Silica-gel supported sulfamic acid (SA/SiO2) as an efficient and reusable catalyst for conversion of ketones into oxathioacetals and dithioacetals
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A simple and efficient method for the conversion of carbonyl compounds to oxathioacetals and dithioacetals using SA/SiO2 as an acid catalyst has been achieved. SA/SiO2 is easily recovered from the reaction mixture and can be reused at least 15 times without loss of catalytic activity.
- Aoyama, Tadashi,Suzuki, Toshihiko,Nagaoka, Takashi,Takido, Toshio,Kodomari, Mitsuo
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p. 553 - 566
(2013/01/15)
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- New phosphonic acid polysilsesquioxane mild solid acid catalysts
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A simple easily scalable one-pot route to new phosphonic acid polysilsesquioxanes, PAPSQ, [(O3/2SiCH2R) x(O3/2SiCHR(CH2)2SiO 3/2)y]n where R = CH2PO 3H2, is described in this paper. Nuclear magnetic resonance (NMR), electron microscopy (SEM), thermogravimetric analysis, nitrogen sorption porosimetry, phosphorus and available acid analysis were used to characterise the new PAPSQ materials. The materials were shown to be very efficient and recyclable mild solid acid catalysts for organic transformations including those relevant to biomass conversion such as esterification, transesterification and dehydration of fructose to the important intermediate 5-hydroxymethylfurfural.
- Sebah, Majda,Maddala, Sai P.,Haycock, Peter,Sullivan, Alice,Toms, Harold,Wilson, John
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- Acetalization allows the photoheterolysis of the Ar-Cl bond in chlorobenzaldehydes and chloroacetophenones
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The nonaccessibility of phenyl cations by irradiation of electron-poor aryl chlorides was circumvented by transforming the carbonyl group of aromatic ketones or aldehydes into the corresponding 1,3-dioxolanes and the carboxyl group of benzoate ester into
- Raviola, Carlotta,Protti, Stefano,Ravelli, Davide,Mella, Mariella,Albini, Angelo,Fagnoni, Maurizio
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supporting information
p. 9094 - 9101
(2013/01/15)
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- Palladium-catalyzed synthesis of terminal acetals via highly selective anti-Markovnikov nucleophilic attack of pinacol on vinylarenes, allyl ethers, and 1,5-dienes
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A palladium-catalyzed reaction of vinylarenes, allyl ethers, and 1,5-dienes with pinacol proceeded via a selective anti-Markovnikov nucleophilic attack to afford corresponding terminal acetals as major products. The bulkiness of pinacol was found to be critical in controlling the regioselectivity. The Royal Society of Chemistry 2012.
- Yamamoto, Mayumi,Nakaoka, Sonoe,Ura, Yasuyuki,Kataoka, Yasutaka
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supporting information; experimental part
p. 1165 - 1167
(2012/02/04)
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- Indium(III) triflate catalysed transacetalisation reactions of diols and triols under solvent-free conditions
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Acyclic acetals and ketals undergo transacetalisation in the presence of catalytic quantities of indium(III) triflate (In(OTf)3) and diols or triols under solvent-free conditions to generate the corresponding cyclic acetals and ketals in excellent yield. The methodology has been further developed to encompass a tandem acetalisation-acetal exchange protocol, which provides a facile and high yielding route to cyclic ketals from unreactive ketones under very mild reaction conditions.
- Smith, Brendan M.,Kubczyk, Tomasz M.,Graham, Andrew E.
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experimental part
p. 7775 - 7781
(2012/09/21)
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- A mild, room-temperature protection of ketones and aldehydes as 1,3-dioxolanes under basic conditions
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Protection of ketones or aldehydes as 1,3-dioxolane derivatives proceeds within minutes at room temperature in the presence of N- hydroxybenzenesulfonamide, its O-benzyl derivative, or the tosyl analogue, in the absence of strong protonic acids, and in the presence of base (Et). Acid-sensitive groups such as O-THP, O-TBS, or N-Boc are unaffected. Copyright
- Hassner, Alfred,Bandi, Chennakesava Reddy,Panchgalle, Sharad
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p. 2773 - 2776
(2013/02/21)
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- Three-dimensional phosphine metal-organic frameworks assembled from Cu(I) and pyridyl diphosphine
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Metal-organic frameworks (MOFs) with phosphine based ligands are extremely attractive for catalysis. In this paper, phosphine has been successfully incorporated for the first time into three-dimensional (3D) MOFs. The MOFs are based on rigid L2M2 dimeric secondary building blocks assembled from Cu(I) and a pyridyl diphosphine ligand, 4-(3,5- bis(diphenylphosphino)phenyl)pyridine, with Br- (CuL-Br), Cl - (CuL-Br), or PF6- (CuL-PF6) as counteranions. The structures have a 4.122 net topology, which can be further simplified to 64.82-qtz. The MOFs contain 1D homochiral channels. The PF6- anions hosted in the 1D channel of CuL-PF6 can be readily exchanged with Br- or Cl- while keeping the framework intact. The materials show anion-tunable flexible porosity. CuL-Br reveals gradual uptake of MeOH, while CuL-PF6 exhibits stepwise sorption for MeOH. The heterogeneous Lewis acid catalytic activity of the MOFs has been shown in ketalization reaction. CuL-Br and CuL-PF6 are active in the reactions between ethylene glycol and 2-butanone/cyclohexanone, up to 93% yield with 0.2 mol % catalyst loading. In contrast, no reaction happens between ethylene glycol and bulky benzophenone, suggesting profound size selectivity. The catalysts can be reused with the framework left intact for three runs without loss of activity.
- Tan, Xin,Li, Lei,Zhang, Jianyong,Han, Xiaorui,Jiang, Long,Li, Fuwei,Su, Cheng-Yong
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experimental part
p. 480 - 485
(2012/06/16)
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- Bis(perfluorooctanesulfonyl)imide supported on fluorous silica gel: Application to protection of carbonyls
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The immobilization of bis(perfluorooctanesulfonyl)imide (HNPf2) on fluorous silica gel (FSG) and its utilization in protection of carbonyls have been investigated. This system is reasonably general and can be applied to converting several carbonyls to the corresponding acetals and ketals in good to excellent yields. There is no need for the use of anhydrous solvents or inert atmosphere. Recycling studies have shown that the FSG-supported HNPf2 catalyst can be readily recovered and reused several times without significant loss of activity.
- Hong, Mei,Xiao, Guomin
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experimental part
p. 121 - 126
(2012/08/28)
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- Self-assembly synthesis of a high-content sulfonic acid group functionalized ordered mesoporous polymer-based solid as a stable and highly active acid catalyst
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A stable and highly active ordered mesoporous polymer-based acid catalyst has been prepared via a simple surfactant templating approach and oxidation treatment. The composition and nanostructure are characterized by XRD, NMR, XPS, TEM, nitrogen sorption, elemental and chemical analysis. The sulfonic acid groups have been anchored within the well-arranged channels of the polymer-based matrix. Even with a high -SO3H group loading (up to about 27.4 wt%) on the mesoporous polymer-based material, the ordered mesostructure and high surface area (~400 m2 g-1) can be retained and the functional moieties are highly chemically accessible. With the large number of acid sites (0.93-2.38 H+ mmol g-1 determined by acid-base titration) and the hydrophobic character, the mesoporous polymer-based solid exhibits unique catalytic performance in acid-catalyzed reactions such as condensation and acetalization, not only high activity (per site yield of bisphenol-A is over 45 in the condensation of phenol and acetone) but also excellent stability. Loss in acidic loading and activity is negligible even after the catalyst is reused 20 times in the acetalization of butanediol and aldehyde. The stability is most likely attributed to the hydrophobic nature of the mesoporous polymer-based solids, which favors the diffusion of water and thereby inhibits the poisoning of acidic sites caused by water generating in the reaction. Moreover, with large mesopores, the diffusion of reactants and products can be promoted and hence the catalytic activity can be further increased.
- Wang, Wei,Zhuang, Xin,Zhao, Qingfei,Wan, Ying
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supporting information; body text
p. 15874 - 15886
(2012/09/05)
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- An efficient photoinduced deprotection of aromatic acetals and ketals
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A novel type of photodeprotection reaction of simple aromatic acetals and ketals is described. The deprotection is highly efficient under optimized conditions. The aromatic ring confers the photoreactivity to the compounds. The efficiency of the process depends on the structure of the acetal moiety. The common minor side reaction, the photooxidation, becomes the major reaction pathway in the cases of cyclic acetals. The use of photon as only reagent makes this procedure especially attractive for acetal deprotection.
- Thevenet, Damien,Neier, Reinhard
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experimental part
p. 331 - 346
(2011/04/22)
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- Indium triflate mediated tandem acetalisation-acetal exchange reactions under solvent-free conditions
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Acyclic acetals and ketals undergo exchange reactions in the presence of catalytic quantities of indium(III) triflate and diols to generate the corresponding cyclic acetals and ketals in excellent yield. The protocol is rapid, employs mild conditions and can be adapted to employ solvent-free reaction conditions. We have further developed this methodology to encompass a tandem acetalisation-acetal exchange protocol which provides facile access to cyclic ketals from unreactive ketones also under very mild, solvent-free reaction conditions.
- Smith, Brendan M.,Graham, Andrew E.
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experimental part
p. 6281 - 6283
(2011/12/14)
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- Mesoporous sulfated zirconia mediated acetalization reactions
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A novel, convenient, one step synthetic procedure for the synthesis of mesoporous sulfated zirconia (m-SZ) using zirconium carbonate complex and its use as solid acid catalyst for the acetalization of different carbonyl compound is reported. The high specific BET surface area (234 m2 g -1) of m-SZ is achieved after the removal of the surfactant (cetyltrymethylammonium bromide, CTAB) through calcination at 550 °C for 6 h. Microscopic analysis indicated the presence of spherical particles with worm like pores. DRIFT (diffuse reflectance FTIR) of pyridine adsorbed m-SZ and NH3-TPD (temperature programmed desorption) analysis suggested the presence of appreciable amount of Bro?nsted acid sites. The synthesized m-SZ showed high catalytic activity towards protection of carbonyl compounds through acetal/ketal formation. For the open ketal (from cyclohexanone and methanol) 97% conversion with 100% selectivity was obtained in 1 h at room temperature under solvent free condition. The catalyst can be easily recycled after separation from the reaction system without considerable loss in catalytic activity.
- Sinhamahapatra, Apurba,Sutradhar, Narottom,Ghosh, Malay,Bajaj, Hari C.,Panda, Asit B.
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experimental part
p. 87 - 93
(2012/04/10)
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- Bismuth compounds in organic synthesis: Synthesis of dioxanes, dioxepines, and dioxolanes catalyzed by bismuth(III) triflate
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A simple method for the synthesis of 1,3-dioxolanes from carbonyl compounds has been developed using 1,2-bis(trimethylsilyloxy)ethane in the presence of bismuth(III) triflate as a catalyst. The bismuth(III) triflate catalyzed synthesis of a range of dioxanes and dioxepines has also been developed. In these latter cases, the carbonyl compound is treated with a diol, and triethyl orthoformate is used as a water scavenger. All these methods avoid the use of a Dean-Stark trap. Georg Thieme Verlag Stuttgart.
- Podgorski, Daniel M.,Krabbe, Scott W.,Le, Long N.,Sierszulski, Paul R.,Mohan, Ram S.
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experimental part
p. 2771 - 2775
(2010/10/02)
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- [Hmim]3PW12O40: A high-efficient and green catalyst for the acetalization of carbonyl compounds
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[Hmim]3PW12O40 was developed and used in the acetalization of carbonyl compounds in excellent yields. The ionic liquid-heteropoly acid hybrid compound and reaction medium formed temperature-dependent phase-separation system with the ease of product as well as catalyst separation. The catalyst was recycled more than 10 times without any apparent loss of catalytic activity.
- Dai, Yan,Li, Bin Dong,Quan, Heng Dao,Lü, Chun Xu
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experimental part
p. 678 - 681
(2011/10/31)
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- Highly efficient and chemoselective acetalization of carbonyl compounds catalyzed by new and reusab e zirconyl triflate, zr0(0tf)2
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Various types of aromatic aldehydes were efficiently converted to their corresponding 1,3-dioxanes and 1,3-dioxolane with 1,3-propanediol and ethylene glycol, respectively, in the presence of catalytic amount of ZrO(OTf) 2 in acetonitrile at room temperature. The catalyst can be reused several times without loss of its catalytic activity. Very short reaction times, selective acetalization of aromatic aldehydes in the presence of aliphatic aldehydes and ketones, very mild reaction conditions, reusability of the catalyst, and easy workup are noteworthy advantages of this method.
- Moghadam, Majid,Mohammadpoor-Baltork, Iraj,Tangestaninejad, Shahram,Mirkhani, Valiollah,Yazdani, Parvin,Ghorjipoor, Saeedeh
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experimental part
p. 131 - 135
(2009/09/30)
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- A convenient method for converting hydroxyacetophenones into their ethylene or trimethylene acetals
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Various types of hydroxyacetophenones are efficiently converted into the corresponding ethylene acetals in the presence of ethane-1,2-diol, triisopropyl orthoformate, and a catalytic amount of cerium(III) trifluoromethanesulfonate under mild reaction conditions. The homologous trimethylene acetals can be also prepared in the same way. Georg Thieme Verlag Stuttgart.
- Ono, Fumiaki,Takenaka, Hirotaka,Fujikawa, Toshikazu,Mori, Masaki,Sato, Tsuneo
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experimental part
p. 1318 - 1322
(2009/12/07)
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- Regioselective transformation of alkynes into cyclic acetals and thioacetals with a gold(I) catalyst: comparison with Br?nsted acid catalysts
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Au(I) catalyzes the transformation of alkynes into cyclic acetals and thioacetals at much higher rate than Br?nsted acids. The reaction appears to be general for a range of alkynes and diols or dithiols, which are efficiently transformed with high selectivities. One of the salient features of this reaction process is the high reactivity of the enol ether or enol thioether intermediates, which undergo a rapid isomerization reaction to afford the cyclic acetals or thioacetals, so that isolation or subsequent activation processes are not required. This type of reactions allows us to synthesize a series of fragrances.
- Santos, Laura L.,Ruiz, Violeta R.,Sabater, Maria J.,Corma, Avelino
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p. 7902 - 7909
(2008/12/21)
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- Hydrogen-bond-directed catalysis: Faster, regioselective and cleaner heck arylation of electron-rich olefins in alcohols
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A general method for the regioselective Heck reaction of electronrich olefins is presented. Fast, highly regioselective Pd-catalysed α-arylation of electron-rich olefins, vinyl ethers (1a-d), hydroxyl vinyl ethers (1e,f), enamides (1g,h) and a substituted vinyl ether (1i) has been accomplished with a diverse range of aryl bromides (2a-r), for the first time, in cheap, green and easily available alcohols with no need for any halide scavengers or salt additives. The reaction proceeds with high efficiency, leading exclusively to the a-products, in 2-propanol and particularly in ethylene glycol. In the latter, the arylation can be catalysed at a palladium loading of 0.1 mol% and finish in as short a time as 0.5 h. The remarkable performance of the alcohol solvents in promoting a regiocontrol is attributed to their hydrogen-bond- donating capability, which is believed to facilitate the dissociation of halide anions from PdII, and hence, the generation of a key ionic Pd II-olefin intermediate responsible for the a product. This belief is further strengthened by the study of a benchmark arylation reaction in 21 different solvents. The study revealed that exclusive α-regioselective arylation takes place in almost all of the protic solvents, and there is a rough correlation between the α-arylation rates and the solvent parameter ETN. The method is simpler, cleaner and more general than those established thus far.
- Hyder, Zeynab,Ruan, Jiwu,Xiao, Jianliang
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experimental part
p. 5555 - 5566
(2009/06/17)
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- Indium(III)trifluoromethanesulfonate as a mild, efficient catalyst for the formation of acetals and ketals in the presence of acid sensitive functional groups
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Aldehydes and ketones, including acetophenone and benzophenone, are readily protected under mild, neutral conditions in the presence of various alcohols or orthoformates and catalytic amounts of indium(III) trifluoromethanesulfonate (0.8 mol %) under either room temperature or mild heating conditions to give the corresponding cyclic and acyclic acetals and ketals in good to excellent yields. Acid sensitive functional groups, N-Boc, THP, and TBDMS do not undergo competitive deprotection under the reported conditions.
- Gregg, Brian T.,Golden, Kathryn C.,Quinn, John F.
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p. 3287 - 3295
(2008/09/21)
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- A green procedure for the protection of carbonyl compounds catalyzed by iodine in ionic liquid
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Aldehydes and ketones are protected with ethylene glycol in the presence of a catalytic amount of iodine in PEG ionic liquid (IL 400) under mild conditions to afford the corresponding ketals in good yields. The recovery of iodine is facilitated by the ionic liquid. The recovered catalyst was reused six times with consistent activity.
- Ren, Yi-Ming,Cai, Chun
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body text
p. 7110 - 7112
(2015/04/15)
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- PALLADIUM CATALYSED HECK ARYLATION OR VINYLATION OF 1-SUBSTITUTED OLEFINS
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The present invention relates to a process for preparing arylated or vinylated olefins.
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Page/Page column 13-14; 16-17; 20
(2008/06/13)
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- Direct synthesis of protected arylacetaldehydes by tetrakis(phosphane)- palladium-catalyzed arylation of ethyleneglycol vinyl ether
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A range of aryl bromides undergo Heck reaction with ethylene glycol vinyl ether, in the presence of [PdCl(C3H5)]2/ cis,cis,cis-1,2,3,4-tetrakis[(diphenylphosphanyl)methyl]cyclopentane as catalyst, to give regioselectively protected arylacetaldehydes in good yields. The β-arylation products were obtained in with 93-100 % selectivity with electron-poor aryl bromides or heteroaryl bromides. Furthermore, this catalyst can be used at low loading, even for reactions with sterically hindered aryl bromides. The aryl vinyl ether intermediates undergo subsequent ketalisation to give the corresponding 2-benzyl-1,3-dioxolane derivatives. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Kondolff, Isabelle,Doucet, Henri,Santelli, Maurice
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p. 765 - 774
(2007/10/03)
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- The Heck reaction of electron-rich olefins with regiocontrol by hydrogen-bond donors
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No salt please: Halide scavengers AgOTf and TlOAc are not required for the Heck coupling of electron-rich olefins with aryl bromides and chlorides. Using ammonium additives, these reactions can be carried out in either an imidazolium ionic liquid or a common molecular solvent, thus furnishing 1,1′- disubstituted olefins in high yields with excellent regioselectivities. (Chemical Equation Presented).
- Mo, Jun,Xiao, Jianliang
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p. 4152 - 4157
(2007/10/03)
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- Palladium-catalysed direct regioselective synthesis of cyclic ketals from electron-rich olefins and aryl bromides in ionic liquids
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The Heck reaction comprises one of the most important carbon-carbon coupling reactions in organic synthesis. The popularity of the reaction is attributable to the broad availability of aryl halides and to the tolerance of the reaction for a wide variety o
- Hyder, Zeynab,Mo, Jun,Xiao, Jianliang
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p. 1699 - 1704
(2007/10/03)
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- Acid-free, organocatalytic acetalization
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The acid-free, organocatalytic acetalization of various aldehydes and ketones with N,N′-bis[3,5-bis(trifluoromethyl)phenyl]thiourea is presented. The neutral, double hydrogen bonding thiourea catalyst can be used at very low loadings of 0.01-1 mol% at room temperature to furnish the respective acetals in 65-99% yield at turnover frequencies around 600 h-1. Acid-labile TBDMS-protected as well as unsaturated aldehydes can be converted efficiently into their acetals utilizing this very mild and highly practical method.
- Kotke, Mike,Schreiner, Peter R.
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p. 434 - 439
(2007/10/03)
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- Reductive cleavage of acetals and ketals with 9-borabicyclo[3.3.1]nonane
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The reductive cleavage of benzaldehyde acetals and acetophenone ketals with the air-stable crystalline 9-borabicyclo[3.3.1]-nonane dimer provides monobenzylated ether derivatives of diols and 1,2-oxygen-transposed β-phenethyl alcohols, respectively. The boron moiety is effectively recovered through simple procedures which involve convenient air-stable reagents and boron byproducts. The process is particularly selective for 1,3-diols giving the more substituted monobenzyl ether derivatives exclusively. With acetophenone ketals both reduction and elimination occur, permitting 9-BBN-H to hydroborate the resulting styrene to produce 1,2-oxygen-transposed β-phenethyl alcohols cleanly. Potential applications of this new process were illustrated with the synthesis of the hallucinogen, mescaline, and the analgesic, ibufenac.
- Soderquist, John A.,Kock, Iveliz,Estrella, Maria E.
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supporting information
p. 1076 - 1079
(2012/12/23)
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- A remarkable iodine-catalyzed protection of carbonyl compounds
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We report here a remarkably simple molecular iodine-catalyzed protection method for various carbonyl compounds as ketals in a general reaction. The iodine-catalyzed reaction of mandelic acid and lactic acid with several aldehydes has furnished a highly diastereoselective synthesis of cis and trans dioxolanones.
- Banik, Bimal K.,Chapa, Marin,Marquez, Jocabed,Cardona, Magda
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p. 2341 - 2343
(2007/10/03)
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- Acidic properties of sulfonic acid-functionalized FSM-16 mesoporous silica and its catalytic efficiency for acetalization of carbonyl compounds
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Propyl-sulfonic acid-functionalized FSM-16 mesoporous silica (SO 3H-FSM) is prepared by a conventional post-modification method. For the acetalization of carbonyl compounds with ethylene glycol, SO 3H-FSM shows a higher rate and 1,3-dioxolane yield than conventional heterogeneous solid acids such as zeolites, montmorillonite K10 clay, silica-alumina, and the sulfonic resin. SO3H-FSM is stable during the reaction, with no leaching and deactivation of sulfonic acid groups, and is reusable without loss of its activity. The acidity and hydrophilicity of SO 3H-FSM are well characterized by the microcalorimetry of NH 3 adsorption, NH3-TPD, and H2O-TPD, and the result is compared with those for various aluminosilicate zeolites (HZSM5, HBEA, HY) and K10 clay. It is found that NH3-TPD is not suitable for characterizing the acidity of SO3H-FSM, because the decomposition of SO3H groups on SO3H-FSM begins above 200°C. An NH 3 adsorption microcalorimetric experiment at 150°C shows that, compared with HZSM5, SO3H-FSM has a smaller number of acid sites but has a similar number of strong acid sites with ammonia adsorption heat above 140 kJ mol-1. Comparison of the structural properties and catalytic results shows that a large pore diameter and low hydrophilicity are required to obtain high activity. Bronsted acid sites with a relatively strong acid strength are more suitable for this reaction, but the high acid concentration is not indispensable. The high activity of SO3H-FSM should be caused by the presence of the strong Bronsted acid sites in the mesopore with a relatively low hydrophilicity, where both reactants can smoothly access the acid sites.
- Shimizu, Ken-Ichi,Hayashi, Eidai,Hatamachi, Tsuyoshi,Kodama, Tatsuya,Higuchi, Tomoya,Satsuma, Atsushi,Kitayama, Yoshie
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p. 131 - 138
(2007/10/03)
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- Direct synthesis of protected arylacetaldehydes by palladium- tetraphosphine-catalyzed arylation of ethyleneglycol vinylether
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Through the use of [PdCl(C3H5)]2/cis,cis, cis-1,2,3,4-tetrakis(diphenylphosphinomethyl) cyclopentane as a catalyst, a range of aryl bromides undergo Heck reaction with ethyleneglycol vinylether to give regioselectively protected arylacetaldehydes in good yields. The β-arylation products were obtained in the range 93-98% selectivity with electron-poor aryl bromides. Furthermore, this catalyst can be used at low loading, even for reactions of sterically hindered aryl bromides. The arylvinyl ethers intermediates undergo subsequent ketalization to give the corresponding 2-benzyl-1,3-dioxolane derivatives.
- Kondolff, Isabelle,Doucet, Henri,Santelli, Maurice
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p. 1561 - 1564
(2007/10/03)
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- A simple and practical synthetic protocol for acetalisation, thioacetalisation and transthioacetalisation of carbonyl compounds under solvent-free conditions
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A wide variety of carbonyl compounds can be converted smoothly to the corresponding acetals on treatment with alcohols or diols and triethyl orthoformate in the presence of a catalytic amount of (bromodimethyl)sulfonium bromide at room temperature. Similarly, various carbonyl compounds can be transformed into the corresponding dithioacetals on reaction with thiol or dithiols at room temperature by employing the same catalyst without any solvent. Moreover, O,O-acetals can also be converted into the corresponding dithioacetals under identical conditions. Some of the major advantages are mild reaction conditions, a high degree of efficiency, compatibilty with other protecting groups and the lack of solvents, particularly for thioacetalisation. In addition, no brominations occur at the double bond or α to the keto position or even in the aromatic ring under these experimental conditions. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
- Khan, Abu T.,Mondal, Ejabul,Ghosh, Subrata,Islam, Samimul
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p. 2002 - 2009
(2007/10/03)
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- Application of Functional Ionic Liquids Possessing Two Adjacent Acid Sites for Acetalization of Aldehydes
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Several acid functional ionic liquids, in which cations possess two adjacent acid sites, were synthesized and used for the acetalization of aldehydes with good catalytic performance under mild reaction conditions.
- Li, Dongmei,Shi, Feng,Peng, Jiajian,Guo, Shu,Deng, Youquan
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p. 3582 - 3585
(2007/10/03)
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- Polyaniline-Supported Sulfuric Acid Salt as a Powerful Catalyst for the Protection and Deprotection of Carbonyl Compounds
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Structurally different carbonyl compounds were converted into their corresponding cyclic acetals using polyaniline-sulfate salt as catalyst in dry toluene in excellent yield. In turn, useful deacetalization in aqueous medium was demonstrated. Chemoselective protection of carbonyl compounds was also demonstrated. The advantages of the polyaniline-sulfate salt are ease of preparation and handling, stability, reusability and activity.
- Palaniappan, Srinivasan,Narender, Puli,Saravanan, Chandrasekaran,Rao, Vaidya Jayathirtha
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p. 1793 - 1796
(2007/10/03)
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