- The construction of novel and efficient hafnium catalysts using naturally existing tannic acid for Meerwein-Ponndorf-Verley reduction
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The conversion of carbonyl compounds into alcohols or their derivatives via the catalytic transfer hydrogenation (CTH) process known as Meerwein-Ponndorf-Verley reduction is an important reaction in the reaction chain involved in biomass transformation. The rational design of efficient catalysts using natural and renewable materials is critical for decreasing the catalyst cost and for the sustainable supply of raw materials during catalyst preparation. In this study, a novel hafnium-based catalyst was constructed using naturally existing tannic acid as the ligand. The prepared hafnium-tannic acid (Hf-TA) catalyst was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and thermogravimetry (TG). Hf-TA was applied in the conversion of furfuraldehyde (FD) to furfuryl alcohol (FA) using isopropanol (2-PrOH) as both the reaction solvent and the hydrogen source. Both preparation conditions and the effects of the reaction parameters on the performance of the catalyst were studied. Under the relatively mild reaction conditions of 70 °C and 3 h, FD (1 mmol) could be converted into FA with a high yield of 99.0%. In addition, the Hf-TA catalyst could be reused at least ten times without a notable decrease in activity and selectivity, indicating its excellent stability. It was proved that Hf-TA could also catalyze the conversion of various carbonyl compounds with different structures. The high efficiency, natural occurrence of tannic acid, and facile preparation process make Hf-TA a potential catalyst for applications in the biomass conversion field.
- Deng, Lijuan,Hao, Jianxiu,He, Runxia,Li, Na,Liu, Quansheng,Wang, Xiaolu,Zhao, Hongye,Zhi, Keduan,Zhou, Huacong
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p. 6944 - 6952
(2020/03/03)
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- Acid Catalysts Based on Mesoporous Aromatic Frameworks in Aldol Condensation of Furfural with Some Carbonyl Compounds
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Aldol condensation of furfural with acetone and a series of aldehydes in the presence of PAF-SO3H acid catalyst based on mesoporous aromatic frameworks was investigated. The reaction course depending on the process temperature, catalyst amount, and reactant ratio was considered for the furfural condensation with acetone as an example. The catalyst can be reused in several cycles without appreciable activity loss.
- Talanova, M. Yu.,Yarchak,Karakhanov
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p. 857 - 864
(2019/08/12)
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- Chichibabin pyridinium synthesis
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Chichibabin pyridine synthesis involves the reaction of three aldehydes and ammonia to form 2,3,5-trisubstituted pyridines. This study examined the synthesis of tetrasubstituted pyridinium from aldehydes and an amine hydrochloride in the presence/absence of Pr(OTf)3. Important insights into the reaction mechanisms of Chichibabin pyridinium synthesis were proposed through the investigation of reaction intermediates along with quantitative GC–MS analysis.
- Imura, Akiho,Tanaka, Nao,Usuki, Toyonobu
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supporting information
p. 489 - 492
(2019/01/15)
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- Synthesis of Guerbet ionic liquids and extractants as β-branched biosourceable hydrophobes
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This study investigates the synthesis of β-branched amines and β-branched quaternary ammonium chloride ionic liquids as novel extractants. The synthesis methodology was tailored to facilitate the reaction scale-up and the use of biorenewable starting materials. The developed process is an overall green, easy and straightforward synthesis of β-branched amines, and ammonium salts, starting from linear aldehydes. In order to evaluate the potential of the synthesised materials in applications, the rheology, density, thermal stability, chemical stability, phase transitions, and mutual solubility with water of the novel extractants was studied.
- Damilano, Giacomo,Binnemans, Koen,Dehaen, Wim
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supporting information
p. 9778 - 9791
(2019/12/02)
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- CONVERSION OF ALCOHOLS TO LINEAR AND BRANCHED FUNCTIONALIZED ALKANES
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Embodiments herein concerns the eco-friendly conversion of simple alcohols to linear or branched functionalized alkanes, by integrated catalysis. The alcohols are firstlyoxidized either chemically or enzymatically to the corresponding aldehydes or ketones, followed by aldol condensations using a catalyst to give the corresponding enals or enones. The enals or enones are subsequently and selectively hydrogenated using a recyclable heterogeneous metal catalyst, organocatalyst or an enzyme to provide linear or branched functionalized alkanes with an aldehyde, keto- or alcohol functionality. The process is also iterative and can be further extended by repeating the above integrated catalysis for producing long-chain functionalized alkanes from simple alcohols.
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Page/Page column 10-11
(2018/03/09)
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- Synthesizing method of 2-butyl-1-octanol
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The invention discloses a synthesizing method of 2-butyl-1-octanol. The method includes the following steps of conducting an aldol condensation reaction with n-caproaldehyde as the initiator to obtain2-butyl-2-octenal, wherein a catalyst in the aldol condensation reaction is barium hydroxide; conducting a primary reduction reaction on 2-butyl-2-octenal to obtain a mixture of aldehyde and alcohol,and conducting a secondary reduction reaction on the mixture of aldehyde and alcohol to obtain 2-butyl-1-octanol, wherein a reducing agent in the primary reduction reaction is palladium on carbon, and a reducing agent in the secondary reduction reaction is sodium borohydride. The method is easy to operate, few byproducts are produced, yield is high, the requirements for devices are not high, andindustrial production is easy.
- -
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Paragraph 0026-0027
(2018/07/15)
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- Guerbet Alcohols: From Processes under Harsh Conditions to Synthesis at Room Temperature under Ambient Pressure
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A novel synthetic approach towards Guerbet alcohols, which are important intermediates in the production of plasticizers, lubricants, and surfactants, was developed. In contrast to the harsh reaction conditions of Guerbet alcohols produced today, which include high temperatures, the new developed process runs at room temperature. The key feature of this alternative process is the combination of organocatalytic and enzymatic steps towards a chemoenzymatic synthesis. In detail, the piperidinyloxyl-catalyzed oxidation of 1-hexanol by using hypochlorite and the lysine-catalyzed homoaldol condensation of the resulting aldehyde were combined with two subsequent enzymatic reductions of the C=C and C=O bonds of the in situ formed 2-branched α,β-unsaturated aldehyde by means of an ene reductase from Gluconobacter oxydans and an alcohol dehydrogenase from Rhodococcus sp. under in situ cofactor regeneration. The desired 2-branched aliphatic primary alcohol was obtained with high conversion and selectivity and without the need for intermediate purifications. Fantastic four: The synthesis of Guerbet alcohols at room temperature under ambient pressure is reported; this is in contrast to today's industrial production, which is performed under harsh reaction conditions. The presented process is based on the combination of two organocatalytic steps with a biocatalytic two-step tandem process starting from readily available aliphatic alcohols. High conversions and selectivities are found for all steps.
- Biermann, Marc,Gru?, Hendrik,Hummel, Werner,Gr?ger, Harald
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p. 895 - 899
(2016/03/15)
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- A comprehensive investigation and optimisation on the proteinogenic amino acid catalysed homo aldol condensation
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A systematic investigation regarding the application of catalytic amounts of all 20 proteinogenic amino acids in the homo aldol condensation of aldehydes is described obtaining excellent yields of the desired α,β-unsaturated aldehyde. These investigations
- Ostrowski, Karoline A.,Lichte, Dominik,Stuck, Moritz,Vorholt, Andreas J.
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supporting information
p. 592 - 598
(2016/01/15)
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- Rhodium-catalyzed homogeneous reductive amidation of aldehydes
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The catalytic reductive amidation of an aldehyde (hexanal) with an amide (acetamide) is reported. Apart from the desired N-hexylacetamide, the two isomeric unsaturated intermediates as well as hexanol are produced together with higher mass products that arise from aldol condensation and diamide coupling of the aldehyde. Screening of different catalyst precursor salts, ligands and reaction conditions led to the finding that the catalytic system based on the (cyclooctadiene)rhodium chloride dimer, [Rh(cod)Cl]2, in combination with the ligand xantphos and an acid co-catalyst results in high selectivity for the desired product. Under optimized conditions nearly full conversion is reached with high selectivity to the desired N-alkylamide and with a very high N-alkylamide/alcohol ratio, while producing only small amounts of by-products. The scope of the reaction has been investigated using different amides as well as aldehydes; the results show the general applicability of this novel reaction, but with electron-withdrawing amides the selectivity to N-alkylamide is lower. NMR studies showed that the nucleophilic addition of acetamide to hexanal is acid catalyzed, forming N-(1-hydroxyhexyl)acetamide in equilibrium with both hexanal and the dehydrated unsaturated imides. A catalytic mechanism is proposed in which a strong acid such as HOTs acts as a co-catalyst by establishing a rapid chemical equilibrium between the aldehyde, acetamide and the intermediates. Furthermore, it is proposed that the presence of acid causes a change in catalytic species, enabling a cationic Rh/xantphos hydrogenation catalyst to selectively hydrogenate the intermediates to N-hexylacetamide in the presence of hexanal. Copyright
- Raoufmoghaddam, Saeed,Drent, Eite,Bouwman, Elisabeth
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supporting information
p. 717 - 733
(2013/04/23)
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- GUERBET ALCOHOLS AND METHODS FOR PREPARING AND USING SAME
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The invention relates to Guerbet alcohol precursors and Guerbet alcohols, as well as to processes for synthesizing them.
- -
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Paragraph 0097; 0098; 00100; 00101; 00102
(2013/10/08)
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- Model studies on the pattern of volatiles generated in mixtures of amino acids, lipid-oxidation-derived aldehydes, and glucose
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The development of flavor and browning in thermally treated foods results mainly from the Maillard reaction and lipid degradation but also from the interactions between both reaction pathways. To study these interactions, we analyzed the volatile compounds resulting from model reactions of lysine or glycine with aldehydes originating from lipid oxidation [hexanal, (E)-2-hexenal, or (2E,4E)-decadienal] in the presence and absence of glucose. The main reaction products identified in these model mixtures were carbonyl compounds, resulting essentially from amino-acid-catalyzed aldol condensation reactions. Several 2-alkylfurans were detected as well. Only a few azaheterocyclic compounds were identified, in particular 5-butyl-2-propylpyridine from (E)-2-hexenal model systems and 2-pentylpyridine from (2E,4E)-decadienal model reactions. Although few reaction products were found resulting from the condensation of an amino acid with a lipid-derived aldehyde, the amino acid plays an important role in catalyzing the degradation and further reaction of these carbonyl compounds. These results suggest that amino-acid-induced degradations and further reactions of lipid oxidation products may be of considerable importance in thermally processed foods.
- Adams, An,Kitryte, Vaida,Venskutonis, Rimantas,De Kimpe, Norbert
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experimental part
p. 1449 - 1456
(2011/10/05)
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- Amino functionalized chitosan as a catalyst for selective solvent-free self-condensation of linear aldehydes
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An aminopropyltrimethoxysilane functionalized chitosan was found to be an efficient solid base catalyst for the self-aldol condensation of linear aldehydes under solvent-free conditions. The modified catalyst was characterized using physical techniques, elemental analysis, FT-IR, and TGA. The modified chitosan was evaluated for the aldol condensation of C3-C7 linear aldehydes in which the selective formation was obtained for α,β-unsaturated aldehydes. A decreasing trend in the conversion from propanal to heptanal was observed. Propanal and pentanal were subjected for detail investigations to study the effect of parameters like amount of catalyst and aldehyde, and temperature on the conversion and selectivity. Kinetic performance of the modified chitosan investigated for a representative aldehyde, pentanal showed that the rate was increased with the catalyst amount, pentanal and temperature. The catalyst was reused up to six cycles without significant loss in its activity and selectivity.
- Jose, Tharun,Sudheesh,Shukla, Ram S.
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experimental part
p. 158 - 166
(2011/02/23)
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- A green method for the self-aldol condensation of aldehydes using lysine
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A self-condensation of aldehydes has been conveniently accomplished by the catalytic action of lysine in water or a solvent-free system under specific emulsion conditions to give α-branched α,β-unsaturated aldehydes in good yields.
- Watanabe, Yutaka,Sawada, Kazue,Hayashi, Minoru
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experimental part
p. 384 - 386
(2010/08/04)
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- Catalysis in flow: The practical and selective aerobic oxidation of alcohols to aldehydes and ketones
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A safe, practical and selective process for the aerobic oxidation of alcohols to aldehydes and ketones has been developed using an Ru catalyst in a continuous flow reactor. Benzylic and allylic alcohols are oxidised selectively to their corresponding aldehydes and ketones, including substrates containing N- and S-heteroatoms. The rate of turnover is compatible with that previously reported using batch or microchannel reactors under optimised conditions. A preliminary kinetic model is derived that is supported by experimental observations. Last but not least, tandem oxidation-olefination may be achieved without the need to isolate the alcohol intermediate or to switch solvent.
- Zotova, Natalia,Hellgardt, Klaus,Kelsall, Geoffrey H.,Jessiman, Alan S.,Hii, King Kuok Mimi
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supporting information; experimental part
p. 2157 - 2163
(2011/02/21)
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- The effects of amine and acid catalysts on efficient chelation-assisted hydroacylation of alkene with aliphatic aldehyde
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Efficient intermolecular hydroacylation of 1-alkene with aliphatic aldehyde was achieved using a catalyst mixture of cyclohexylamine, p-trifluoromethylbenzoic acid, Wilkinson's complex and 2-amino-3-picoline. The formation of unwanted aldol side-product w
- Jo, Eun-Ae,Jun, Chul-Ho
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experimental part
p. 3338 - 3340
(2009/08/17)
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- N,N-dialkylpolyhydroxyalkylamines
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N,N-Dialkylpolyhydroxyalkylamines may be made by the reductive alkylation of an N-alkylpolyhydroxyalkylamine with an aldehyde or ketone, or with an equivalent compound, in the presence of a transition metal catalyst and hydrogen. The reaction is performed in a reaction solvent that contains at least 30 wt% of an organic solvent. The use of a sufficiently high proportion of an appropriate organic solvent in the reaction mixture reduces the amount of water present in the reaction mixture, and provides rapid reaction rates and high yields of the desired product. The N,N-dialkylpolyhydroxyalkylamines may be used in a wide variety of applications.
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Page/Page column 14-15
(2008/06/13)
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- Synthesis of aliphatic ketones from allylic alcohols through consecutive isomerization and chelation-assisted hydroacylation by a rhodium catalyst
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Abstract: An allylic alcohol, utilized as a precursor for an aliphatic aldehyde, reacted with olefins to afford aliphatic ketones in the presence of RhCl(PPh3)3, 2-amino-4-picoline, aniline, and benzoic acid through a tandem reaction of an isomerization and a chelation-assisted hydroacylation.
- Lee, Dae-Yon,Moon, Choong Woon,Jun, Chul-Ho
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p. 3945 - 3948
(2007/10/03)
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- Chemistry of trichlorofluromethane: Synthesis of chlorofluromethyl phenyl sulfone and fluoromethyl phenyl sulfone and some of their reactions
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It was observed that the reaction of CFCl3 with thiophenoxide gave only 10% of the corresponding thioether. On the other hand, these thioethers could be prepared in excellent yield from diaryl disulfides and CFCl3 in the presence of sodium hydroxymethanesulfinate in aqueous DMF at 4 atm pressure of nitrogen. Dechlorination of the thioether (PhSCFCl2) with different reducing agents were studied. Most of the reducing agents eliminated both fluorine and chlorine functionalities or gave the hydrolyzed products. But its sulfone on treatment with Zinc in methanol gave monochlorofluoromethyl and fluoromethyl phenyl sulfone in good yields. Darzens reaction of these compounds was also studied.
- Saikia,Tsuboi
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p. 643 - 647
(2007/10/03)
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- Alcohol oxidation and aldol condensation during base-catalyzed reaction of primary alcohols with 1-chloroanthraquinone
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When chloroanthraquinone is treated with primary alcohols under basic conditions, the notoriously low yields observed for substitution result in part from oxidation of the alcohol followed by aldol condensation. (C) 2000 Elsevier Science Ltd.
- Shabany,Abel,Evans,McRobbie,Gokel
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p. 6705 - 6708
(2007/10/03)
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- Aldol Reaction and Robinson-Type Annelation Catalyzed by Lanthanoid Triisopropoxides
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Lanthanoid triisopropoxides are active catalysts for aldol reactions.Aldehydes give the corresponding β-hydroxyaldehydes at low temperatures in good yields, whereas ketones are less reactive, but form condensation products at high temperatures.Exceptionally, γ- or δ-diketones easily undergo condensation to give five- and six-membered unsaturated ketones in high yields.The lanthanoid propoxides, catalyzing the Michael addition of ketones to α,β-unsaturated ketones, which give δ-diketones, are also good catalysts for the Robinson-type annelation.In these reactions, the catalytic activity of the lanthanum propoxide is higher than those of the heavy lanthanoid propoxides, and is almost comparable to that of sodium isopropoxide.Since aluminum triisopropoxide shows poor activity, the lanthanoid propoxides are considerably basic for trivalent metal alkoxides.
- Okano, Tamon,Satou, Yoshikazu,Tamura, Motoshi,Kiji, Jitsuo
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p. 1879 - 1886
(2007/10/03)
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- Catalytic action of azolium salts. VI. Preparation of benzoins and acyloins by condensation of aldehydes catalyzed by azolium salts
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Benzoins 4 (2-hydroxyethanones substituted with aryl groups at the 1- and 2-positions) were prepared by self-condensation of aromatic aldehydes 3 using catalytic amounts of azolium salts 1 and 2 in excellent yields. 1,3-Dimethylbenzimidazolium iodide (2) was an effective catalyst for the preparation of acyloins 6 (2-hydroxyethanones substituted with alkyl groups at the 1- and 2-positions) by self-condensation of aliphatic aldehydes 5. On the other hand, an attempt at the condensation of hexanal (5d) catalyzed by 1,3-dimethylimidazolium iodide (1) failed to yield the acyloin 6d, and instead the aldol-type condensed product 8d was obtained.
- Miyashita,Suzuki,Iwamoto,Higashino
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p. 2633 - 2635
(2007/10/02)
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- Regiospecificity in Reactions of Metal Phenoxides. Synthesis of 2,2'-alkylidenebisphenols
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The reactions between aryloxymagnesium bromides (1) with linear aliphatic aldehydes (2) and their acetals (10) in aprotic solvents of variable donicity have been investigated.In benzene high ortho-regiospecificity is observed in all cases, although with the aldehyde (2) the yield of 2,2'-alkylidenebisphenols (5) is usually low because of the competing aldehyde self-condensation.This process is avoided using diethyl acetals as electrophilic reagents which give the products (5) in good yields.
- Casiraghi, Giovanni,Casnati, Giuseppe,Pochini, Andrea,Ungaro, Rocco
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p. 805 - 808
(2007/10/02)
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- REACTION OF ENOLATES OF ACYLTRIMETHYLSILANES WITH ALDEHYDES. CANNIZZARO TYPE OXIDATION-REDUCTION REACTION WITH A TRIMETHYLSILYLCARBONYL GROUP
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The reaction of an acyltrimethylsilane enolate with 2 eq of an aldehyde gives a 1:2 adduct, while that with the enolate of an α-chloroacyltrimethylsilane affords an α,β-unsaturated aldehyde as a 1:1 adduct accompanied by the carboxylic acid derived from the starting aldehyde.An oxidation-reduction reaction mechanism on the trimethylsilylcarbonyl group has been proposed.
- Kuwajima, Isao,Matsumoto, Kazuhisa,Sugahara, Shuichi
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p. 525 - 528
(2007/10/02)
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