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Acetals
Kinds of Acetals Terms modified by Acetals Selected AbstractsAcrolein Diethyl Acetal: A Three-Carbon Homologating Reagent for the Synthesis of ,-Arylpropanoates and Cinnamaldehydes by Heck Reaction Catalyzed by a Kaiser Oxime Resin Derived PalladacycleEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 18 2008Emilio Alacid Abstract A polymer palladacycle derived from Kaiser oxime resin was used as a source of palladium(0) in the chemoselective Heck reaction of acrolein diethyl acetal with aryl halides under ligand-free conditions. The use of typical Heck conditions afforded 3-arylpropionic esters, and the process can be directed to the synthesis of cinnamaldehydes under Cacchi conditions. These processes take place with rather low loading of the catalyst, which can be recovered by simple filtration and reused for at least five runs without competitive dehalogenation. This is the first time that a supported palladium complex has been reused under Cacchi conditions. ICP-OES analyses of the Pd content of the crude products in both transformations indicated lower leaching for the esters than for the aldehydes in the range up to 0.08 ppm for the esters and 0.8 ppm for the aldehydes.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] ChemInform Abstract: Gold-Catalyzed Dealkoxylative Carbocyclization/[3 + 3] Annulation Cascade of Acetal,Allene or Ketal,Allene Substrates.CHEMINFORM, Issue 37 2010Tse-Min Teng Abstract Acetal-allene or ketal-allene compounds undergo the title cascade reaction with 2-substituted allylsilanes, a phenol, or enolizable ketones to give a wide variety of tri- and tetracyclic carbocycles as well as oxapolycyclic compounds with good stereocontrol in general. [source] ChemInform Abstract: A Convenient Method for the Synthesis of (Z)-,-Fluoroacrylates: Lewis Base-Catalyzed Carbonyl Fluoroolefination Using Fluoro(trimethylsilyl)ketene Ethyl Trimethylsilyl Acetal.CHEMINFORM, Issue 1 2009Makoto Michida Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: A Convenient Method for the Lewis Base-Catalyzed Synthesis of ,,,-Unsaturated Carboxylic Esters Using Trimethylsilylketene Ethyl Trimethylsilyl Acetal and Carbonyl Compounds.CHEMINFORM, Issue 47 2008Makoto Michida Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Bio-inspired Polyene Cyclization: Synthesis of Tetracyclic Terpenoids Promoted by Steroidal Acetal,SnCl4.CHEMINFORM, Issue 29 2008Yu-Jun Zhao Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] (Triisopropylsilyl)acetaldehyde Acetal as a Novel Protective Group for 1,2-Diols.CHEMINFORM, Issue 46 2006Jun'ichi Uenishi Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Conjugate Addition of a Silyl Ketene Acetal to ,,,-Unsaturated Lactones.CHEMINFORM, Issue 35 2006Rudhramyna Gnaneshwar Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Lewis Base Catalyzed, Enantioselective Aldol Addition of Methyl Trichlorosilyl Ketene Acetal to Ketones.CHEMINFORM, Issue 45 2005Scott E. Denmark Abstract For Abstract see ChemInform Abstract in Full Text. [source] Direct Synthesis of 3-Arylpropionic Acids by Tetraphosphine/Palladium Catalyzed Heck Reactions of Aryl Halides with Acrolein Ethylene Acetal.CHEMINFORM, Issue 12 2005Mhamed Lemhadri No abstract is available for this article. [source] The Mukaiyama,Michael Addition of a ,,,-Dimethyl Substituted Silyl Ketene Acetal to ,,,-Unsaturated Ketones Using Tetra-n-butylammonium Bibenzoate as a Nucleophilic Catalyst.CHEMINFORM, Issue 47 2003Rudhramyna Gnaneshwar Abstract For Abstract see ChemInform Abstract in Full Text. [source] Highly Enantioselective Mukaiyama Aldol Reaction of ,,,-Dichloro Ketene Silyl Acetal: An Efficient Synthesis of a Key Intermediate for Diltiazem.CHEMINFORM, Issue 25 2003Ritsuo Imashiro Abstract For Abstract see ChemInform Abstract in Full Text. [source] A Novel Approach to the Practical Synthesis of Sulfides: An InBr3,Et3SiH Catalytic System Promoted the Direct Reductive Sulfidation of Acetals with DisulfidesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 24 2009Norio Sakai Abstract We have demonstrated a facile and direct synthesis of sulfide derivatives using acetals and ketals, derived from aromatic/conjugated aldehydes and aromatic ketones, with disulfides and the InBr3,Et3SiH reducing system. We also succeeded in developing an unprecedented one-pot preparation of an aliphatic sulfide from a disulfide and an aliphatic acetal. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Rapid and Easy Access to (E)-1,3-Enynes, 1,3-Diynes and Allenes Starting from Propargylic Acetals, Exploiting the Different Reactivity of Lithium and Mixed Lithium,Potassium Organometallic ReagentsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 35 2007Marco Blangetti Abstract The treatment of propargylic acetals with various lithium and mixed lithium,potassium Schlosser reagents, has allowed a one-pot synthesis of (E)-1,3-enynes, 1,3-diynes and allenes, depending on the reaction conditions and the selected base. Various reaction conditions were investigated in order to control the selectivity of the reactions and to obtain pure products. The metallation,elimination sequence in the presence of a suitable electrophile has provided a linear route to functionalized (E)-conjugated enynes, diynes and allenes.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Highly Shape-Selective, Biomimetic, and Efficient Deprotection of Carbonyl Compounds Masked as Ethylene Acetals or Dioxolanes Produced from 1,2-EthanediolEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 18 2003Hong-Bing Ji Abstract A simple, mild, efficient, and organic solvent-free biochemical approach for the deprotection of carbonyl compounds protected as 1,3-dioxolanes through the use of cyclodextrins as catalysts has been developed. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Pentafluorophenylammonium Trifluoromethanesulfonimide: Mild, Powerful, and Robust Catalyst for Mukaiyama Aldol and Mannich Reactions between Ketene Silyl Acetals and Ketones or Oxime EthersADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 7 2010Ryohei Nagase Abstract Pentafluorophenylammonium trifluoromethanesulfonimide (C6F5N+H3,NTf2,) promotes Mukaiyama aldol and Mannich reactions using ketene silyl acetals with ketones and oxime ethers, respectively. The present robust method is mild, but powerful enough to utilize less accessible electrophiles such as enolizable ketones and oxime ethers to produce a variety of ,-hydroxy esters and ,-alkoxyamino esters, respectively. Mechanistic investigation revealed in situ generation of trimethylsilyl bistriflimide [Tf2N(TMS)], the truly active catalyst, which was supported by rational 1H,NMR measurements. [source] Domino Reaction of Acyclic ,,,-Dialkenoylketene S,S -Acetals and Diamines: Efficient Synthesis of Tetracyclic Thieno[2,3- b]thiopyran-Fused Imidazo[1,2- a]pyridine/Pyrido[1,2- a]pyrimidinesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 14 2006Fushun Liang Abstract A series of unusual fused tetraheterocyclic compounds 3, consisting of a thiopyran (ring A), a thiophene (ring B), a pyridine (ring C), and an imidazole or a pyrimidine (ring D) core, with a bridgehead nitrogen and an angular methyl group, were successfully synthesized by a catalyst-free, one-pot, two-component domino reaction of 4-(4-methyl-1,3-dithiol-2-ylidene)-1,7-bis(aryl/heteroaryl)hepta-1,6-diene-3,5-dione 2 and diamines. In this reaction, up to five new bonds were formed accompanied by the CS bond cleavage of the 1,3-dithiole ring of 2, with water as the only by-product. [source] Synthesis, oxidation and dehydrogenation of cyclic N,O - and N,S -Acetals.JOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 5 2006-thiazolidines, . Transformation of N, S -acetals: 3-Acylbenzothiazolines The dehydrogenations with iron(III) chloride, potassium permanganate, and for the first time, CAN, tris-[trinitrato-cerium(IV)]-paraperiodate (TTNCPP), and (diacetoxyiodo)benzene (IBDA) are investigated. Hydrogen peroxide, sodium periodate, potassium permanganate, and ammonium cerium(IV) nitrate (CAN) oxidation of chiral benzothiazolines, O - and O,N -acylated derivatives of the condensates of D-galactose with 2-aminothiophenols or L-cysteine, are also reported. [source] Berichtigung: Palladium-Catalyzed ,-Arylation of ,,,-Unsaturated Esters from Silyl Ketene AcetalsANGEWANDTE CHEMIE, Issue 40 2010David No abstract is available for this article. [source] Palladium-Catalyzed ,-Arylation of ,,,-Unsaturated Esters from Silyl Ketene Acetals,ANGEWANDTE CHEMIE, Issue 33 2010David Smarter Katalysator: Eine Methode für die Palladium-katalysierte ,-Arylierung von ,,,-ungesättigten Estern wurde entwickelt, die über Silylketenacetale verläuft und ohne Fluorid-Aktivatoren auskommt. Die Kupplung gelingt mit elektronenreichen und elektronenarmen Aryl- und Vinylbromiden in hohen Ausbeuten, und andere funktionelle Gruppen werden gut toleriert. [source] Regioselective Oxidative Cleavage of Benzylidene Acetals: Synthesis of ,- and ,-Benzoyloxy Carboxylic Acids,ANGEWANDTE CHEMIE, Issue 4 2010Ponminor, Senthil Kumar Ruthenium hat doppelt Spaß: Das Synthesepotential der hoch regio- und stereoselektiven Titelreaktion, die zwei durch RuCl3 in Kombination mit NaIO4 ermöglichte oxidative Spaltungsschritte nutzt (siehe Beispiel; Bz=Benzoyl), wurde mit der Synthese der biologisch aktiven cis -(2R,3S) - 3-Hydroxypipecolsäure aus D -Glucose nachgewiesen. [source] Radical Cyclization of , -Bromo Aluminum Acetals: An Easy Approach to , -Lactols,ANGEWANDTE CHEMIE, Issue 50 2009Anne Boussonnière Ringe um Aluminium: Ein effizientes Verfahren zur Radikalcyclisierung von , -Bromestern ist die hier beschriebene Reduktion der Ester mit DIBAL-H bei niedriger Temperatur zu Aluminiumacetalen, die in Gegenwart von nBu3SnH und Et3B cyclisieren (siehe Schema). Diese Eintopfumsetzung liefert polysubstituierte , -Lactole in hohen Ausbeuten, und die milden Reaktionsbedingungen ermöglichen die Synthese von säureempfindlichen Derivaten. [source] Acceptorless Dehydrogenation of Alcohols: Perspectives for Synthesis and H2 Storage.CHEMCATCHEM, Issue 1 2009Anja Friedrich Without acception: Acetals are selectively obtained from acceptorless alcohol dehydrogenation (AAD) of aliphatic primary alcohols catalyzed by a ruthenium complex bearing an acridine-based PNP pincer ligand. This unprecedented reaction represents a new tool for one-step acetal synthesis under mild reaction conditions and demonstrates that AAD selectivity can be controlled by changes to the catalyst ligand sphere. [source] ChemInform Abstract: Pentafluorophenylammonium Trifluoromethanesulfonimide: Mild, Powerful, and Robust Catalyst for Mukaiyama Aldol and Mannich Reactions Between Ketene Silyl Acetals and Ketones or Oxime Ethers.CHEMINFORM, Issue 38 2010Ryohei Nagase Abstract The catalyst allows facile access to ,-hydroxy esters, ,-amino esters, and 5-oxo esters. [source] ChemInform Abstract: Synthesis of Dialkyl Ethers from Organotrifluoroborates and Acetals.CHEMINFORM, Issue 16 2010T. Andrew Mitchell Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Radical Cyclization of ,-Bromo Aluminum Acetals: An Easy Approach to ,-Lactols.CHEMINFORM, Issue 14 2010Anne Boussonniere Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: C-Phosphorylated 4,5-Dihydrothiazoles as Products of the Reaction of Acetals of ,-Thiocyanato-,-phosphorylacetaldehydes with Thioamides.CHEMINFORM, Issue 14 2010Kh. A. Asado Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Practical and Robust Method for Stereoselective Preparations of Ketene Silyl (Thio)acetal Derivatives and NaOH-Catalyzed Cross-Claisen Condensation Between Ketene Silyl Acetals and Methyl Esters.CHEMINFORM, Issue 44 2009Kenta Takai Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Regio- and Stereoselective Generation of Alkenylindium Compounds from Indium Tribomide, Alkynes, and Ketene Silyl Acetals.CHEMINFORM, Issue 41 2009Yoshihiro Nishimoto Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: KBrO3/MoO3: An Efficient Reagent System for the Oxidative Deprotection of Semicarbazones, 1,1-Diacetates and Acetals.CHEMINFORM, Issue 36 2009Farhad Shirini Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: AuCl3 -Catalyzed Hydroalkoxylation of Conjugated Alkynoates: Synthesis of Five- and Six-Membered Cyclic Acetals.CHEMINFORM, Issue 32 2009Alejandro Dieguez-Vazquez Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] | ||||||||||||||||||||||||||||