- One-pot Synthesis of Acetals by Tandem Hydroformylation-acetalization of Olefins Using Heterogeneous Supported Catalysts
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Abstract: A green route for one?pot synthesis of acetals by tandem hydroformylation?acetalization of olefins using supported Rh?based?catalysts was developed. Experimental results demonstrated that suitable Rh loading (1 wt%) with appropriate reaction temperature (120?°C) and reaction time (8?h) were favorable for the formation of acetals, and a high acetals selectivity of 94.6% was achieved. More importantly, the selectivity to valuable linear products was enhanced in this tandem catalysis. Based on the catalytic mechanism study, highly dispersed RhOx nanoparticles and abundant acid sites on the supports were responsible for the hydroformylation and acetalization, respectively. Graphical abstract: One-pot synthesis of acetals directly from olefins with high selectivity was achieved over heterogeneous bifunctional catalysts via tandem hydroformylation-acetalization. [Figure not available: see fulltext.]
- Li, Xiao,Qin, Tingting,Li, Liusha,Wu, Bo,Lin, Tiejun,Zhong, Liangshu
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p. 2638 - 2646
(2021/01/05)
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- Chemoselective Nucleophilic Functionalizations of Aromatic Aldehydes and Acetals via Pyridinium Salt Intermediates
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The development of a novel chemoselective functionalization can diversify the strategy for synthesizing the target molecules. The perfect chemoselectivity between aromatic and aliphatic aldehydes is difficult to achieve by the previous methods. The aromatic aldehyde-selective nucleophilic addition in the presence of aliphatic aldehydes was newly accomplished. Namely, the aromatic aldehyde-selective nucleophilic addition using arenes and allyl silanes proceeded in the presence of trialkylsilyl triflate and 2,2′-bipyridyl, while the aliphatic aldehydes completely remained unchanged. The reactive pyridinium-type salt intermediate derived from an aromatic aldehyde chemoselectively underwent the nucleophilic substitution. Moreover, the aromatic acetals as the protected aldehydes could be directly transformed into similar pyridinium salt intermediates, which reacted with various nucleophiles coexisting with the aliphatic aldehydes.
- Kawajiri, Takahiro,Kato, Maho,Nakata, Hiroki,Goto, Ryota,Aibara, Shin-Yo,Ohta, Reiya,Fujioka, Hiromichi,Sajiki, Hironao,Sawama, Yoshinari
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p. 3853 - 3870
(2019/03/07)
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- Palladium on Carbon-Catalyzed Chemoselective Oxygen Oxidation of Aromatic Acetals
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The development of an unprecedented chemoselective transformation has contributed to forming a novel synthetic process for target molecules. Chemoselective oxidation of aromatic acetals has been accomplished using a reusable palladium on carbon catalyst under atmospheric oxygen conditions to form ester derivatives with tolerance of aliphatic acetals and ketals.
- Yasukawa, Naoki,Asai, Shota,Kato, Maho,Monguchi, Yasunari,Sajiki, Hironao,Sawama, Yoshinari
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supporting information
p. 5604 - 5607
(2016/11/17)
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- A recyclable fluorous hydrazine-1,2-bis(carbothioate) with NCS as efficient catalysts for acetalization of aldehydes
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A fluorous hydrazine-carbothioate organocatalyst was prepared. Together with NCS, the catalyst showed a good activity in acetalization of aldehydes and alcohols. It could be recovered from the reaction mixture by fluorous solid-phase extraction (F-SPE) with excellent purity for direct reuse.
- Zhu, Yi-Wei,Yi, Wen-Bin,Cai, Chun
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supporting information
p. 890 - 892
(2013/07/05)
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- Method for the selective formation of dimethyl acetals in the presence of hydroxylamine
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An inexpensive and mild method for the formation of dimethyl acetals from the corresponding aldehydes is achieved using hydroxylamine and methanol under neutral conditions at room temperature. Notably, the reaction is selective for aldehydes in the presence of ketones, rendering this an example of a chemoselective acetalization. For saturated, sterically accessible aldehydes, catalytic amounts of hydroxylamine may be employed to attain the corresponding dimethyl acetal as the sole product in good to excellent yield. Unsaturated and hindered aldehydes required stoichiometric amounts of hydroxylamine but provided dimethyl acetals as the major product in typically excellent yield. In some cases, the corresponding oxime was also observed but may be separated from the acetal by flash column chromatography or distillation. The involvement of an intermediate oxime compound is postulated. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications to view the free supplemental file. Taylor & Francis Group, LLC.
- Mickelsen, Ky J.,Tajc, Chelsea M.,Greenwood, Kevin R.,Browder, Cindy C.
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experimental part
p. 186 - 194
(2011/10/31)
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- NCS with thiourea as highly efficient catalysts for acetalization of aldehydes
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NCS/thiourea-mediated acetalization of aldehydes and alcohols has rapidly provided acetals in almost quantitative yields.
- Mei,Bentley,Du
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supporting information; experimental part
p. 4199 - 4200
(2009/10/04)
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- Zinc chloride as an efficient catalyst for chemoselective dimethyl acetalization
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Commercially available anhydrous zinc chloride has been found to be a highly efficient catalyst for dimethyl acetalization in high yields by treatment of aldehydes and ketones with trimethyl orthoformate in methanol-cyclohexane at reflux temperature. Copyright Taylor & Francis Group, LLC.
- Roy, Anupam,Rahman, Matiur,Das, Sudarshan,Kundu, Dhiman,Kundu, Shrishnu Kumar,Majee, Adinath,Hajra, Alakananda
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experimental part
p. 590 - 595
(2009/07/04)
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- Ruthenium(III) chloride-catalyzed chemoselective synthesis of acetals from aldehydes
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A mild and chemoselective acetalization procedure for the protection of various aldehydes in the presence of ketones is described.
- De, Surya K.,Gibbs, Richard A.
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p. 8141 - 8144
(2007/10/03)
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- A remarkable bismuth nitrate-catalyzed protection of carbonyl compounds
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Bismuth nitrate has been found to be an outstanding catalyst for the protection of carbonyl compounds as acetal, ketal, mixed ketal and thioketal with an excellent yield.
- Srivastava, Neeta,Dasgupta, Swapan K.,Banik, Bimal K.
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p. 1191 - 1193
(2007/10/03)
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- Solvolysis of 1-decenyl(phenyl)iodonium tetrafluoroborate: Mechanisms of nucleophilic substitution and elimination
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Solvolysis of (E)-1-decenyl(phenyl)iodonium tetrafluoroborate 1 was carried out in some alcohols, acetic acid, and mixed aqueous alcoholic solvents at 50-60°C and the effects of added carboxylates and other salts were also examined in methanol. Reaction products include enol derivatives (substitution) and 1-decyne (elimination) as well as iodobenzene. Rates for the solvolysis increase with increasing nucleophilicity of the solvent but have no correlation with the solvent ionizing power. The substitution occurs mostly via inversion of configuration, and is concluded to follow the in-plane SN2 mechanism with a minor concomitant out-of-plane SN2 pathway. The reactions with the deuterated substrates show that stronger bases of pKa of the conjugate acid > 3 induce exclusively α-elimination of 1 in methanol. However, both α- and β-elimination occur in neutral methanol in a ratio of about 3/1 besides the substitution. Mechanisms for these reactions are proposed.
- Okuyama, Tadashi,Imamura, Shohei,Ishida, Yoshimi
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p. 543 - 548
(2007/10/03)
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- Preparation and Properties of New Surfactants Containing D-Glucosamine as the Building Block
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Three types of new surfactants were prepared by using N-acetyl-D-glucosamine as a starting material.The first type of surfactant, sodium methyl 4,6-O-alkylidene-2-(carboxylatomethylamino)-2-deoxy-D-glucopyranoside, was prepared successively by the following treatments: methyl glucosidation of N-acetyl-D-glucosamine, transacetalization with an appropriate aldehyde dimethyl acetal, deacetylation, and finally reaction of the resulting methyl-4,6-O-alkylidene-2-amino-2-deoxy-D-glucopyranoside (2-amino precursor) with bromoacetic acid.The reaction of this 2-amino precursor with methyl iodide yielded the second type of surfactant, methyl 4,6-O-alkylidene-2-deoxy-2(trimethylammonio)-D-glucopyranoside iodide, in excellent yield.The last type of compound, sodium methyl 2-acetamide-4,6-O-alkylidene-3-O--2-deoxy-D-glucopyranoside, was synthesized by the reaction of methyl 2-acetamide-4,6-O-alkylidene-2-deoxy-D-glucopyranoside with 2-chloropropionic acid.Concerning the two carboxylate types of surfactants, the compounds containing a C9 or C11 hydrophobic chain in the alkylidene part showed higher water solubility than the corresponding compounds containing a C7 hydrophobic chain.Both the micelle-forming property and the ability to lower the surface tension of these carboxylate types of compounds increased with an increase in the length of the hydrophobic chain in the alkylidene part.These compounds can be applied to new acid-decomposable types of cleavable surfactants because they contain an acetal group.The acetal bond of the ammonium type of compound was cleaved more slowly than that of the corresponding carboxylate types of surfactants in 2percent aqueous HCl solution.The biodegradabilities of these compounds were also determined.KEY WORDS: Acetalization, acid decomposition properties, biodegradability, D-glucosamine, surface-active properties.
- Kida, Toshiyuki,Yurugi, Keiji,Masuyama, Araki,Nakatsuji, Yohji,Ono, Daisuke,Takeda, Tokuji
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p. 773 - 780
(2007/10/03)
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- TiCl4-Catalyzed Addition of HN3 to Aldehydes and Ketones. Thermolysis and Photolysis of α-Azido Ethers
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Aldehydes react with hydrazoic acid and alcohols in the presence of catalytic amounts of TiCl4 to produce α-azido ethers.The conversion of simple ketones to methyl α-azido alkyl ethers can be accomplished by means of hydrazoic acid and methyl orthoformate.Both gas-phase thermolysis and photolysis of representative α-azido ethers were studied and shown to produce mainly imino ethers.In the thermolysis, migratory preference decreases in the series H >> CH3 > Ph >> OR.
- Hassner, Alfred,Fibiger, Richard,Amarasekara, Ananda S.
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