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Operational Simplicity (operational + simplicity)
Selected AbstractsHighly Efficient One-Pot Synthesis of 2-Substituted Quinazolines and 4H -Benzo[d][1,3]oxazines via Cross Dehydrogenative Coupling using Sodium HypochloriteADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 2-3 2010C. Uma Maheswari Abstract This communication describes a catalyst-free synthesis of 2-substituted quinazolines and 4H -benzo[d][1,3]oxazines using commericially available sodium hypochlorite as oxidant. Operational simplicity, mild reaction conditions and the ability to construct structurally diverse 2-quinazolines and 2-substituted 4H -benzo[d][1,3]oxazines by this method render it to be a practical alternative for the synthesis of these heterocycles. [source] Diverse Asymmetric Quinolizidine Synthesis: A Stereodivergent One-Pot ApproachADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 2-3 2010Wei Zhang Abstract A diverse stereodivergent organocatalytic one-pot addition/cyclization/annulation sequence to optically active quinolizidine derivatives from easily available starting materials is presented. The one-pot sequence relies on a pyrrolidine-catalyzed enantioselective conjugate addition of electron-deficient amide ,-carbons to ,,,-unsaturated aldehydes, spontaneous hemiaminal formation and acid-catalyzed/mediated N -acyliminium ion cyclization to give the quinolizidine framework. Simple tuning of the reaction conditions in the N -acyliminuim ion cyclization step provides a diastereomeric switch, which gives access to both of the two bridgehead epimers through kinetic, thermodynamic or chelation control. The methodology display a broad substrate scope that is demonstrated by the stereoselective formation of indolo-, thieno-, benzofuro-, furo- and different benzoquinolizidine derivatives with high atom efficiency, up to >99% ee and up to >95:5 dr. Due to its efficiency, synthetic diversity and operational simplicity, this protocol has the potential to find important use as a key step in natural product synthesis, biochemistry and pharmaceutical science. The stereochemical outcome of the one-pot sequence was investigated, and the mechanism and origin of stereoselectivity of the different steps is discussed. [source] An Effective Bismuth-Catalyzed Benzylation of Arenes and HeteroarenesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2006Magnus Rueping Abstract A highly efficient Bi(OTf)3 -catalyzed benzylation of arenes and heteroarenes has been developed. The mild reaction conditions, high yields, operational simplicity and practicability, broad scope, and remarkably low catalyst loading render this environment friendly process an attractiv approach to diarylmethane derivatives. The extension to an intramolecular variant of this procedure provides a valuable route to substituted fluorenes. [source] A facile and efficient synthesis of N -substituted furo[3,4- b]indeno[2,1- e]pyridine analogues of azapodophyllotoxin via microwave-assisted multicomponent reactionsJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 5 2009Feng Shi The efficient and facile synthesis of N -substituted furo[3,4- b]indeno[2,1- e]pyridine analogues of azapodophyllotoxin was achieved via microwave-assisted multicomponent reactions of aldehyde, 2H -indene-1,3-dione and 4-(arylamino)furan-2(5H)-one in glycol without catalyst. This method has the obvious advantages over traditional heating ones on short reaction time, high yield, operational simplicity as well as being environmental friendly. J. Heterocyclic Chem., (2009). [source] Sulfamic acid catalyzed one-pot synthesis of 2,5-diaryl-1,3,4-oxadiazoles under microwave irradiation and conventional heatingJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 2 2009J. Venu Madhav Sulfamic acid has been found to be an efficient catalyst for the one-pot synthesis of novel 2,5-diaryl-1,3,4-oxadiazoles by condensation of different coumarinoyl hydrazides with various coumarinoyl or quinolinoyl chlorides under microwave irradiation and conventional heating. Some of the advantages of this method are low reaction times, operational simplicity, and high yields. J. Heterocyclic Chem., (2009) [source] Highly efficient bimetallic iron-palladium catalyzed Michael-type Friedel,Crafts reactions of indoles with chalconesAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 3 2009Yue-Hua Gao Abstract Iron,palladium is a superior bimetallic catalyst in the presence of acetylacetone (Acac) with remarkable synergistic effect for the Michael-type Friedel,Crafts reactions of indoles with chalcones. This catalytic system has the advantages of mild reaction conditions, smaller amount of metal salts, high yields of the desired products and operational simplicity, which make it a useful and promising process for the synthesis of indole derivatives. Copyright © 2009 John Wiley & Sons, Ltd. [source] ChemInform Abstract: Sodium Silicate-Catalyzed Multicomponent Synthesis of Pyridine Dicarbonitriles.CHEMINFORM, Issue 41 2010Majid M. Heravi Abstract Advantages of the title multicomponent synthesis are low cost, operational simplicity and minimal environmental impact. [source] Enantioselective Organocatalytic Addition of Oxazolones to 1,1-Bis(phenylsulfonyl)ethylene: A Convenient Asymmetric Synthesis of Quaternary ,-Amino AcidsCHEMISTRY - A EUROPEAN JOURNAL, Issue 18 2010Andrea-Nekane Abstract A new, easy, and highly enantioselective method for the synthesis of quaternary ,-alkyl-,-amino acids based on organocatalysis is reported. The addition of oxazolones to 1,1-bis(phenylsulfonyl)ethylene is efficiently catalyzed by simple chiral bases or thioureas. The reaction affords ,,,-disubstituted ,-amino acid derivatives with complete C4 regioselectivity and with excellent yields and enantioselectivities. This methodology is complementary to previously reported enantioselective approaches to quaternary ,-amino acids and allows the synthesis of ,-phenyl-,-alkyl-,-amino acids and ,- tert -butyl-,-alkyl-,-amino acids. It has distinct advantages in terms of operational simplicity, enviromentally friendly conditions, and suitability for large-scale reactions. [source] Coming of Age: Sustainable Iron-Catalyzed Cross-Coupling ReactionsCHEMSUSCHEM CHEMISTRY AND SUSTAINABILITY, ENERGY & MATERIALS, Issue 5 2009Waldemar Maximilian Czaplik Abstract Iron-catalyzed cross-coupling reactions have, over the past years, developed to maturity and today are an integral part of the organic chemist's toolkit. They benefit from low costs, operational simplicity, and high reactivity and thus constitute the "green" sister of the palladium and nickel establishment. This timely Review traces back major achievements, discusses their mechanistic background, and highlights numerous applications to molecular synthesis. Iron-catalyzed carbon,carbon bond-forming reactions have matured to an indispensable class of reactions in organic synthesis. The advent of economically and ecologically attractive iron catalysts in the past years has stepped up the competition with the established palladium and nickel catalyst systems that have dominated the field for more than 30 years, but suffer from high costs, toxicity, and sometimes low reactivity. Iron-catalyzed protocols do not merely benefit from economic advantages but entertain a rich manifold of reactivity patterns and tolerate various functional groups. The past years have witnessed a rapid development with ever-more-efficient protocols for the cross-coupling between alkyl, alkenyl, alkynyl, aryl, and acyl moieties becoming available to organic chemists. This Review intends to shed light onto the versatility that iron-catalyzed cross-coupling reactions offer, summarize major achievements, and clear the way for further use of such superior methodologies in the synthesis of fine chemicals, bioactive molecules, and materials. [source] | ||||||||||