- Solvent-free Chemoselective Synthesis of 1,1-diacetates Catalyzed by Iron Zirconium Phosphate
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In the present study, a mild, rapid, and efficient method for the protection of aldehydes with acetic anhydride (AA) in the presence of iron zirconium phosphate (ZPFe), at room temperature is reported. Selective conversion of aldehydes was observed in the presence of ketones. Under these conditions, different aldehydes bearing electron-withdrawing and electron-donating substituents were reacted with AA and the corresponding 1,1-diacetates (acylals) were obtained in high to excellent yields. The steric and electronic properties of the different substrates had a significant influence on the reaction conditions. Also, the deprotection of 1,1-diacetates has been achieved using this catalyst in water. The catalyst was characterized by several physico-chemical techniques. It was recovered easily from the reaction mixture, regenerated, and reused at least 7 times without significant loss in catalytic activity. This protocol has the advantages of easy availability, stability, reusability of the eco-friendly catalyst, chemoselectivity, simple experimental and work-up procedure, solvent-free conditions and only a stoichiometric amount of AA is needed.
- Karimi, Hirbod
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p. 1000 - 1010
(2015/12/01)
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- PROCESS FOR PRODUCING ESTER COMPOUND HAVING a,?-UNSATURATED BOND
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A process for producing an α,β-unsaturated bond-containing ester compound, comprising: reacting an internal olefin or a cyclic olefin having one carbon-carbon double bond or more at a position other than terminals of a molecule thereof (the internal olefin and the cyclic olefin may each contain a hetero atom) with a carboxylic acid in an amide-based solvent in the presence of a palladium catalyst, a base, and molecular oxygen, thereby bonding a carboxyl group of the carboxylic acid to at least one of carbon atoms constituting the carbon-carbon double bond and carbon atoms at allylic positions of the internal olefin or the cyclic olefin, to obtain an ester compound having an α,β-unsaturated bond, the amide-based solvent being represented by the following formula (1): (in the formula (1), R1 represents an alkyl group having 1 to 4 carbon atoms; R2 and R3 each independently represent an alkyl group having 1 to 4 carbon atoms or an aryl group; and when R1 and R2 are alkyl groups, R1 and R2 may be bonded to each other to form a ring structure).
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Page/Page column 9-10
(2013/02/27)
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- ZSM-5-SO3H as a novel, efficient, and reusable catalyst for the chemoselective synthesis and deprotection of 1,1-diacetates under eco-friendly conditions
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ZSM-5 has been modified as supported sulfuric acid (ZSM-5-SO3H) and introduced for the first time as a mild, convenient, reusable, and heterogeneous catalyst. Various types of aldehydes were efficiently converted to their 1,1-diacetates using a catalytic amount of ZSM-5- SO3H in excellent yields under solvent-free and heterogeneous conditions at room temperature. The deprotection of 1,1-diacetates has also been achieved using this novel catalyst in ethanol. The procedure is operationally simple, environmentally benign, and only a stoichiometric amount of anhydride is used. Springer-Verlag 2011.
- Massah, Ahmad Reza,Kalbasi, Roozbeh Javad,Shafiei, Anahita
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experimental part
p. 643 - 652
(2012/07/14)
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- Ultrasound-assisted synthesis of acylals from aldehydes using Mg(CH 3SO3)2-HOAC
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An efficient method for the synthesis of acylals from different aldehydes and acetic anhydride in the presence of magnesium methanesulfonate-acetic acid under ultrasound irradiation at room temperature is achieved. Only 1.5mol% of magnesium methanesulfonate and a small quantity of acetic acid are needed to effect the reaction. Selective conversion of aldehydes is observed in the presence of ketones. The catalyst remains active and exhibits no substantial loss of activity or selectivity in up to three reaction cycles.
- Liu, Qing,Ai, Hong-Mei,Feng, Shuai
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experimental part
p. 122 - 127
(2011/11/01)
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- Chromic(III) sulfamate as a versatile catalyst for organic synthesis
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Chromic sulfamate was synthesized and used as catalyst for the first time in various organic reactions such as the transformation of aldehydes or ketones and indole to bis(indolyl)methanes, the transformation of aldehydes and acetic anhydride to 1,1-diacetates and Biginelli reaction. The advantages of the chromic sulfamate are ease of preparation, easy handling, simple work-up and versatility.
- Liu, Qing,Li, Zhen
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experimental part
p. 3208 - 3210
(2012/02/03)
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- Polystyrene-supported, Al(OTf)3-catalyzed chemoselective synthesis of acylals from aldehydes
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Cross-linked polystyrene-supported aluminium triflate [Ps-Al(OTf)3] has been shown to be a mild, efficient, and chemoselective heterogeneous Lewis acid catalyst for acetylation of aldehydes with acetic anhydride. The catalyst can be recovered simply and reused efficiently at least five times without any noticeable loss of catalytic activity. Copyright Taylor & Francis Group, LLC.
- Boroujeni, Kaveh Parvanak
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experimental part
p. 277 - 284
(2011/03/20)
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- Synthesis and characterization of BEA-SO3H as an efficient and chemoselective acid catalyst
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BEA zeolite was synthesized under hydrothermal condition and modified with various amounts of chlorosulphonic acid. It was characterized by XRD, XRF, FT-IR, BET, thermogravimetric analysis and SEM techniques. Catalytic activity of BEA-SO3H was tested for the synthesis of 1,1-diacetates from a variety of aromatic and aliphatic aldehydes including those carrying electron donating or withdrawing substituents by acetic anhydride. At optimized conditions, The BEA-SO3H (28 wt.%) catalyst showed good yield at very short time for the synthesis and deprotection of 1,1-diacetates. Furthermore, BEA-SO3H was found to be recyclable for the protection of aldehydes with acetic anhydride under solvent-free and room temperature conditions. This method is a green approach for the protection of aldehydes in the presence of ketones.
- Kalbasi, Roozbeh Javad,Massah, Ahmad Reza,Shafiei, Anahita
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experimental part
p. 51 - 59
(2011/04/15)
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- Chemoselective synthesis of 1,1-diacetates from aldehydes using anhydrous cobalt(II) bromide under solvent-free conditions
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A mild and efficient method has been developed for the chemoselective preparation of 1,1-diacetates (acylals) from aldehydes catalyzed in the presence of a catalytic amount (0.1mmol) of anhydrous cobalt(II) bromide under solvent-free conditions. The remarkable selectivity under mild and neutral conditions, excellent yields, short reaction time, and easily available and inexpensive catalyst are important features of this method.
- Meshram, Gangadhar A.,Patil, Vishvanath D.
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experimental part
p. 442 - 449
(2010/04/02)
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- Synthesis of 1,1-diacetates using a new combined catalytic system: Copper p-toluenesulfonate/HOAc
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Copper p-toluenesulfonate acetic acid has been established as an efficient combined catalytic system for chemoselective conversion of aldehydes to diacetates in high yields at ambient temperature in short reaction times. For the catalytic system, the amount of copper p-toluenesulfonate reduced to 0.3 mol%. After the reaction, copper p-toluenesulfonate can be easily recovered and reused for at least 10 runs. Copyright Taylor & Francis Group, LLC.
- Wang, Min,Song, Zhiguo,Gong, Hong,Jiang, Heng
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p. 961 - 966
(2008/09/17)
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- An efficient method for the synthesis of acylals from aldehydes under solvent-free conditions catalyzed by antimony trichloride
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A mild and efficient method has been developed for the preparation of acylals from aldehydes catalyzed by antimony trichloride under solvent-free conditions in very good to excellent yields. The easy availability, low cost, and ease of handling of the catalyst make this procedure especially attractive for large-scale synthesis. Copyright Taylor & Francis Group, LLC.
- Bhattacharya, Asish K.,Mujahid, Mohammad,Natu, Arvind A.
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p. 128 - 134
(2008/03/14)
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- A versatile and practical synthesis of 1,1-diacetates from aldehydes catalyzed by cyanuric chloride
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Structurally diverse aldehydes are successfully converted into 1,1-diacetates with acetic anhydride using cyanuric chloride as a mild, convenient and inexpensive catalyst under solvent-free conditions. The noteworthy features of the present system are shorter reaction times, and mild and solvent-free conditions. Furthermore, it offers chemoselective protection of aldehydes.
- Bandgar, Babasaheb P.,Joshi, Neeta S.,Kamble, Vinod T.
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p. 489 - 492
(2008/02/11)
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- Acetic acid-assisted copper methanesulfonate catalyst for chemoselective conversion of aldehydes to acylals
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A new catalytic system has been discovered by combining copper methanesulfonate with acetic acid for chemoselective conversion of aldehydes to acylals in high yields at ambient temperature under solvent-free conditions. The efficiency of this system might result from the "double activation" of Bronsted-Lewis acid catalysis on aldehydes. Copyright Taylor & Francis Group, LLC.
- Wang, Min,Gong, Hong,Jiang, Heng,Wang, Zhichang
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p. 1953 - 1960
(2007/10/03)
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- An efficient procedure for the synthesis of 1,1-diacetates from aldehydes with acetic anhydride catalyzed by silica sulfate
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The reaction of aldehyde with acetic anhydride catalyzed by silica sulfate results in 1,1-diacetates in high yields at room temperature.
- Jin, Tong-Shou,Zhao, Ying,Gu, Shu-Qing,Liu, Li-Bin,Li, Tong-Shuang
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p. 1054 - 1056
(2007/10/03)
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- Reinvestigation of the mechanism of gem-diacylation: Chemoselective conversion of aldehydes to various gem-diacylates and their cleavage under acidic and basic conditions
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The mechanism of gem-diacylate formation has been studied extensively using tetrabutylammonium tribromide (TBATB) as the catalyst. The reaction proceeds by a nucleophilic attack of an anhydride on an aldehydic carbonyl group, nucleophilic attack of the hemiacylate intermediate on a second molecule of the anhydride, followed by an intermolecular attack of a second acetate group to regenerate the anhydride. gem-Diacylates of various aliphatic and aromatic aldehydes were obtained directly from the reaction of a variety of aliphatic and aromatic acid anhydrides in the presence of a catalytic quantity of tetrabutylammonium tribromide (TBATB) under solvent-free conditions. A significant electronic effect was observed during its formation as well as deprotection to the corresponding aldehyde. Chemoselective gem-diacylation of the aromatic aldehyde containing an electron-donating group has been achieved in the presence of an aldehyde containing an electron-withdrawing group. Deprotection of the gem-diacylate to the parent carbonyl compound can be accomplished in methanol in presence of the same catalyst. Here again, chemoselective deprotection of the gem-diacylate of a substrate containing an electron-donating group has been achieved in the presence of a substrate containing an electron-withdrawing group. Both the acid and base stability order of the various gem-diacylates examined follow a similar order. The stability order determined from the present study is: gem-dibenzoate > gem-dipivalate > gem-diisobutyrate > gem-diacetate > gem-dipropionate. All the gem-diacylals are more stable under basic conditions than acidic condition. No correlation was found between the stability order and the pKa's of the corresponding acids; rather, the stability order is directly related to the steric crowding around the carbonyl carbon. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.
- Kavala, Veerababurao,Patel, Bhisma K.
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p. 441 - 451
(2007/10/03)
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- Indium tribromide as a highly efficient and versatile catalyst for chemoselective synthesis of acylals from aldehydes under solvent-free conditions
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A mild and efficient method has been developed for the chemoselective preparation of acylals from aldehydes in the presence of catalytic amounts (0.01-1.0 mol%) of InBr3 under solvent-free conditions in very good to excellent yields.
- Yin, Liang,Zhang, Zhan-Hui,Wang, Yong-Mei,Pang, Mei-Li
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p. 1727 - 1730
(2007/10/03)
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- Facile synthesis of 1,1-diacetates from aldehydes using environmentally benign solid acid catalyst under solvent-free conditions
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Variety of aromatic and aliphatic aldehydes are converted into their 1,1-diacetates in the presence of environmentally benign Mo/TiO 2-ZrO2 solid acid catalyst in good to excellent yields under solvent-free conditions.
- Reddy, Benjaram M.,Sreekanth, Pavani M.,Khan, Ataullah
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p. 1839 - 1845
(2007/10/03)
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- Lithium trifluoromethanesulfonate (LiOTf) as a recyclable catalyst for highly efficient acetylation of alcohols and diacetylation of aldehydes under mild and neutral reaction conditions
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A variety of alcohols and aldehydes were reacted with acetic anhydride at room temperature in the presence of a catalytic amount of lithium triflate (LiOTf) to produce the corresponding esters and 1,1-diacetates, respectively, in good to excellent yields under essentially neutral reaction conditions. Sensitive functional groups such as PhCO2-, OMe, and OTBDMS ethers survived intact under the described reaction conditions.
- Karimi, Babak,Maleki, Jafar
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p. 4951 - 4954
(2007/10/03)
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- Zinc tetrafluoroborate-catalyzed efficient conversion of aldehydes to geminal diacetates and cyanoacetates
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A trace of an aqueous solution of zinc tetrafluoroborate was demonstrated to catalyze the conversion of an aldehyde to its 1,1-diacetate by acetic anhydride without any solvent. A similar reaction of an aldehyde with a mixture of potassium cyanide and acetic anhydride in methylene chloride was also catalyzed by Zn(BF4)2 to provide the corresponding geminal cyanoacetate.
- Ranu, Brindaban C.,Dutta, Jyotirmoy,Das, Arijit
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p. 366 - 367
(2007/10/03)
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- A mild and efficient method for the chemoselective synthesis of acylals from aldehydes and their deprotections catalysed by ceric ammonium nitrate
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A mild and efficient method has been developed for the chemoselective synthesis of geminal diacetates (acylals) from aldehydes using acetic anhydride in the presence of a catalytic amount of ceric ammonium nitrate in excellent yield. Ketones are found to be unaffected under the reaction conditions. The deprotections of acylals by using water and ceric ammonium nitrate have also been achieved.
- Roy, Subhas Chandra,Banerjee, Biplab
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p. 1677 - 1678
(2007/10/03)
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- Geminal dicarboxylates as carbonyl surrogates for asymmetric synthesis. Part I. Asymmetric addition of malonate nucleophiles
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Asymmetric alkylations of allylic geminal dicarboxylates with dialkyl malonates have been investigated. The requisite allylic geminal dicarboxylates are prepared in good yields and high isomeric purities by two catalytic methods, ferric chloride-catalyzed addition of acid anhydrides to α,β-unsaturated aldehydes and palladium-catalyzed isomerization and addition reactions of propargylic acetates. The complex of palladium(0) and the chiral ligand derived from the diamide of trans-1,2-diaminocyclohexane and 2-diphenylphosphinobenzoic acid most efficiently catalyzed the asymmetric process to provide allylic carboxylate esters with high ee. By systematic optimization studies, factors affecting the enantioselectivity of the reaction have been probed. In general, higher ee's have been achieved with those conditions which facilitate kinetic capture of the incipient π-allylpalladium intermediate. These conditions also proved effective for achieving high regioselectivities. The minor regioisomeric product was formed when reactive substrates or achiral ligands were employed for the reaction, and could be minimized through the use of the chiral ligand. Under the established conditions, the alkylation of various gem-dicarboxylates afforded monoalkylated products in high yields with greater than 90% ee. The process constitutes the equivalent of an addition of a stabilized nucleophile to a carbonyl group with high asymmetric induction.
- Trost,Lee
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p. 3671 - 3686
(2007/10/03)
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- Facile preparation of 1,1-diacetates from aldehydes with acetic anhydride catalysed by TiO2/SO42- solid superacid
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A facile and efficient synthesis of 1,1-diacetates in excellent yields from aldehydes with acetic anhydride catalysed by TiO2/SO42- solid superacid.
- Jin, Tong-Shou,Ma, Yan-Ran,Sun, Xu,Liang, Dan,Li, Tong-Shuang
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- The chemistry of acylals. 3. Cyanohydrin esters from acylals with cyanide reagents
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(equation presented) When treated with KCN in DMSO at room temperature, acylals from aliphatic aldehydes gave the corresponding cyanohydrin esters in good to excellent yields. Acylals from aromatic aldehydes were less reactive and gave several byproducts in addition to fair yields of cyanohydrin under the same conditions. Trimethylsilyl cyanide mixed with titanium(IV) chloride afforded cyanohydrin esters in good to excellent yields from both aliphatic and aromatic aldehydes.
- Sandberg, Marcel,Sydnes, Leiv K.
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p. 687 - 689
(2007/10/03)
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- Mild and Efficient Conversion of Aldehydes to 1,1-Diacetates Catalyzed with N-Bromosuccinimide (NBS)
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Aldehydes react with acetic anhydride in the presence of a catalytic amount of N-bromosuccinimide (NBS) to give their corresponding 1,1-diacetates (gem-diacetates) in good to excellent yields.
- Karimi, Babak,Seradj, Hassan,Ebrahimian, G. Reza
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p. 623 - 624
(2007/10/03)
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- Synthesis of 1,1-Diacetates from Aldehydes using Trimethylchlorosilane and Sodium Iodide as Catalyst
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A variety of aldehydes react with acetic anhydride in the presence of trimethylchlorosilane and sodium iodide or trimethylchlorosilane alone to afford 1,1-diacetates in excellent yields.
- Deka, Nabajyoti,Borah, Ruli,Kalita, Dipok J.,Sarma, Jadab C.
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- Facile Synthesis of 1,1-Diacetates from Aldehydes Using Montmorillonite K-10 Clay under Microwave Irradiation
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Selective and easy synthesis of acylals in dry media using montmorillonite K-10 clay in an Erlenmeyer flask under microwave activation in remarkably reduced reaction time is described.
- Karmakar, Dipankar,Prajapati, Dipak,Sandhu, Jagir S.
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p. 382 - 383
(2007/10/03)
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- Sulfated Zirconia: an Efficient Catalyst for the Synthesis of 1,1-Diacetates from Aldehydes and Ketones
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A variety of aldehydes and ketones react with acetic anhydride in the presence of catalytic amounts of solid sulfated zirconia to afford the corresponding 1,1-diacetates in excellent yields.
- Raju, Satya V. N.
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- An efficient synthesis of diacetates from aldehydes using beta zeolite
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A variety of aldehydes react with acetic anhydride in the presence of catalytic amount of β zeolite to afford the corresponding 1,1 diacetates in good to excellent yields.
- Kumar, Pradeep,Hegde, Vishnumurthy R.,Kumar, T. Pavan
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p. 601 - 602
(2007/10/02)
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- Diels-Alder Route to Potential Trichothecene Precursors
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2-Methyl-3-yn-2-ol (9) is efficiently converted into 6-formyl-3,6-dimethylcyclohex-2-enyl acetate (4b) and into 6-acetyl-3,6-dimethylcyclohex-2-enyl acetate (4c) via highly regio- and stereo-selective Diels-Alder cycloadditions of 3-methylbuta-1,3-dienyl acetate (2b).The cycloadduct (4b) is converted by base into 4a,5,6,8a-tetrahydro-4a,7-dimethylcoumarin (13b), whilst the cycloadduct (4c) yields 2,3,4a,5,6,8a-hexahydro-2-hydroxy-2,4a,7-trimethylchroman-4-one (15), the structure of which was confirmed by X-ray analysis.Both (13b) and (15) possess a number of structural features of the trichothecenes and may be of value in their total synthesis.
- Banks, Robert E.,Miller, Allen J.,Nunn, John M.,Stanley, Philip,Weakley, Timothy J. R.,Ullah, Zakir
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p. 1096 - 1102
(2007/10/02)
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