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Tandem Process (tandem + process)

Distribution by Scientific Domains
Chemistry100%

Selected Abstracts

Ruthenium-Catalyzed Reduction of Allylic Alcohols: An Efficient Isomerization/Transfer Hydrogenation Tandem Process.

CHEMINFORM, Issue 43 2007
Victorio Cadierno
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]

Palladium-Catalyzed trans-Selective Alkynylation,Alkylation Tandem Process for the Synthesis of (E)-3-Alkyl-1-trialkylsilyl-3-alken-1-ynes.

CHEMINFORM, Issue 3 2006
Ei-ichi Negishi
No abstract is available for this article. [source]

Efficient Tandem Process for the Catalytic Deprotection of N-Allyl Amides and Lactams in Aqueous Media: A Novel Application of the Bis(allyl),Ruthenium(IV) Catalysts [Ru(,3:,2:,3 -C12H18)Cl2] and [{Ru(,3:,3 -C10H16)(,-Cl)Cl}2],

CHEMISTRY - A EUROPEAN JOURNAL, Issue 23 2007
Victorio Cadierno Dr.
Abstract An operationally simple and highly efficient methodology for the removal of the allyl protecting group in amides and lactams has been developed by using the commercially available bis(allyl),ruthenium(IV) catalysts [Ru(,3:,2:,3 -C12H18)Cl2] (C12H18=dodeca-2,6,10-triene-1,12-diyl) and [{Ru(,3:,3 -C10H16)(,-Cl)Cl}2] (C10H16=2,7-dimethylocta-2,6-diene-1,8-diyl). The tandem process, which takes place in aqueous media and proceeds in a one-pot manner, involves the initial isomerization of the CC bond of the allyl unit and subsequent oxidative cleavage of the resulting enamide. [source]

A Simple Synthesis of Functionalized 3-Bromocoumarins by a One-Pot Three-Component Reaction

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 6 2010
Davide Audisio
Abstract Functionalized 3-bromocoumarins 2 have been prepared by a simple one-pot bromination/Wittig/cyclization tandem process from methyl (triphenylphosphoranylidene)acetate, N -bromosuccinimide and a series of 2-hydroxybenzaldehydes. Owing to the commercial availability of salicylaldehyde derivatives, this approach offers such a diverse range of compounds that it fulfills the recent demand for the generation of large combinatorial chemical libraries based on the coumarin scaffold. [source]

One-Pot Synthesis of 3-Aryltetramic Acids

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 6 2010
Aurélie Mallinger
Abstract Tetramic acids substituted in the 3-position by various aryl groups were prepared in one-pot from amino esters and methyl arylacetates, by treatment with potassium tert -butoxide. A tandem process, involving the formation of an amide and a condensation reaction, is likely to occur. N -Unsubstituted tetramic acids were obtained from adducts containing a N -(2,4-dimethoxybenzyl) group. [source]

A New, Expeditious Entry to the Benzophenanthrofuran Framework by a Pd-Catalyzed C - and O -Arylation/PIFA-Mediated Oxidative Coupling Sequence

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 12 2005
Fátima Churruca
Abstract The synthesis of a series of 2,3-diarylbenzo[b]furans starting from 1,2-diarylethanones and 1,2-dibromoarenes proceeds by means of both homogeneous and polymer-anchored palladium catalysts. This tandem process can be effectively halted at the C -arylation step, thus providing key o -bromoarylated deoxybenzoin intermediates in good yields. The efficient oxidative coupling leading to benzo[b]phenanthro[9,10- d]furans is carried out using the safer hypervalent iodine reagent PIFA. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source]

Arylethyne Bromoboration,Negishi Coupling Route to E - or Z -Aryl-Substituted Trisubstituted Alkenes of ,98% Isomeric Purity.

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 4 2010
New Horizon in the Highly Selective Synthesis of Trisubstituted Alkenes
Abstract The hitherto unprecedented palladium-catalyzed cross-coupling of (Z)-,-bromo-,-arylethenylboranes can be made to proceed satisfactorily through (1) the use of highly catalytically active bis(tri- tert -butylphosphine)palladium or dichloro[N,N -bis-(2,6-diisopropylphenyl)imidazol-2-yl](m -chloropyridine)palladium and (2) conversion of the dibromoboryl group to the (pinacol)boryl group. Thus, a wide variety of carbon groups can be used to substitute bromine in ,98% stereo- and regioselectivity, while suppressing the otherwise dominant ,-debromoboration. Together with the alkylethyne-based protocols, the alkyne bromoboration,Negishi coupling tandem process has emerged as the most widely applicable and highly selective route to trisubstituted alkenes including those that are otherwise difficult to access. [source]

Highly Efficient Synthesis of Stereodefined Multisubstituted 1,4-Dicyano- and 1-Cyano-1,3-butadienes and Their Reactions with Organolithium Reagents

CHEMISTRY - A EUROPEAN JOURNAL, Issue 22 2007
Congyang Wang Dr.
Abstract Stereodefined multisubstituted 1-cyano- and 1,4-dicyano-1,3-butadiene derivatives were obtained in excellent yields of the isolated product from their corresponding monohalo- and dihalobutadienes and CuCN. This reaction proceeded with high stereoselectivity and retention of the stereochemistry of the starting halobutadienes. A study of the utility of the thus-obtained 1-cyano- and 1,4-dicyano-1,3-butadiene derivatives was demonstrated by their reactions with organolithium reagents. 2H -Pyrrole or iminocyclopentadiene derivatives were formed in high yields from 1-cyano-4-halo-1,3-butadienes and organolithium reagents. When 1,4-dicyano-1,3-butadienes were treated with organolithium reagents followed by trapping with electrophiles, a tandem process took place to afford 2H -pyrrolyl nitriles in excellent yields. Reduction of 1,4-dicyano-1,3-butadiene derivatives with LiAlH4 showed novel reaction patterns relative to normal nitriles. [source]

Silver versus Gold Catalysis in Tandem Reactions of Carbonyl Functions onto Alkynes: A Versatile Access to Furoquinoline and Pyranoquinoline Cores

CHEMISTRY - A EUROPEAN JOURNAL, Issue 19 2007
Thomas Godet
Abstract An efficient and versatile tandem process of acetalization and cycloisomerization reactions has been developed for the reactions of 1-alkynyl-2-carbonylquinoline substrates. The reaction occurs thanks to AuI and AgI catalysis. Silver(I) catalysis has been extensively studied (11 different silver species) on a broad range of quinoline derivatives (variation of alkyne substituent, of carbonyl function and of nucleophiles), leading to a variety of furoquinoline and pyranoquinoline moieties. An insight is given for the presumed mechanism along with DFT-B3,LYP/6,31G** calculations to address the 6- endo and 5- exo regioselectivities observed. [source]