Mild Reaction Conditions (mild + reaction_condition)

Distribution by Scientific Domains
Distribution within Chemistry

Kinds of Mild Reaction Conditions

  • very mild reaction condition


  • Selected Abstracts


    Reaction of Bis(alkynyl)silanes with Tris(pentafluorophenyl)borane: Synthesis of Bulky Silole Derivatives by Means of 1,1-Carboboration under Mild Reaction Conditions

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 7-8 2009
    Gereon Dierker
    Abstract The strong Lewis acid tris(pentafluorophenyl)borane [B(C6F5)3] reacts rapidly with dimethylbis(phenylethynyl)silane (1c) at room temperature in toluene by shift of a pentafluorophenyl (C6F5) group and formation of a new carbon-bis(pentafluorophenyl)boron linkage [CB(C6F5)2] in a sequence of 1,1-carboboration reactions to yield the 4-bis(pentafluorophenyl)boryl/3-pentafluorophenyl-substituted 1,1-dimethyl-2,5-diphenylsilole derivative 7c. The analogous reaction of bis(trimethylsilylethynyl)diphenylsilane (1d) with tris(pentafluorophenyl)borane gave the corresponding boryl-substituted silole derivative (7d) featuring six bulky substituents attached at the central heterocyclic framework. Both the starting materials (1c, 1d) and the products (7c, 7d) were characterized by X-ray crystal structure analyses. [source]


    Palladium-Catalyzed Ring-Expansion Reaction of Indoles with Alkynes: From Indoles to Tetrahydroquinoline Derivatives Under Mild Reaction Conditions,

    ANGEWANDTE CHEMIE, Issue 24 2010
    Zhuangzhi Shi
    Ausbaufähiges Indol: Die hoch selektiv mit O2 als Oxidationsmittel und unter doppelter C-H-Aktivierung verlaufende Titelreaktion öffnet einen neuen Zugang zu polysubstituierten 4,5-Dihydrocyclopenta[c]chinolinen (siehe Schema). Außerdem wurden Einblicke in den Mechanismus dieser Ringerweiterung erhalten. [source]


    ChemInform Abstract: A Facile Generation of C,S Bonds via One-Pot, Odorless and Efficient Thia-Michael Addition Reactions Using Alkyl, Aryl or Allyl Halides, Thiourea and Electron-Deficient Alkenes in Wet Polyethylene Glycol (PEG 200) under Mild Reaction Conditions.

    CHEMINFORM, Issue 44 2009
    Habib Firouzabadi
    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: Selective Iridium-Catalyzed Alkylation of (Hetero)Aromatic Amines and Diamines with Alcohols under Mild Reaction Conditions.

    CHEMINFORM, Issue 32 2009
    Benoit Blank
    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: Trichloromelamine (TCM) , Catalyzed Efficient and Selective Thioacetalization of Aldehydes and Transthioacetalization of Acetals and Oxathioacetals under Mild Reaction Conditions.

    CHEMINFORM, Issue 50 2008
    Hassan Hazarkhani
    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: Highly Efficient Oxidation of Alcohols Using Oxone® as Oxidant Catalyzed by Ruthenium Complex under Mild Reaction Conditions.

    CHEMINFORM, Issue 49 2008
    Zi Qiang Lei
    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]


    N-Bromosuccinimide and Iodine-Catalyzed Highly Efficient Deoxygenation of Sulfoxides to Thioethers Using 3-Mercaptopropionic Acid under Mild Reaction Conditions.

    CHEMINFORM, Issue 52 2003
    Babak Karimi
    Abstract For Abstract see ChemInform Abstract in Full Text. [source]


    ChemInform Abstract: Electrochemical Activation of Carbon Dioxide in Ionic Liquid: Synthesis of Cyclic Carbonates at Mild Reaction Conditions.

    CHEMINFORM, Issue 20 2002
    Hongzhou Yang
    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]


    Selective Iridium-Catalyzed Alkylation of (Hetero)Aromatic Amines and Diamines with Alcohols under Mild Reaction Conditions

    CHEMISTRY - A EUROPEAN JOURNAL, Issue 15 2009
    Benoît Blank
    Abstract Selective amine alkylation: A P,N-ligand-stabilized iridium complex has been used as an efficient catalyst for the alkylation of (hetero)aromatic amines with alcohols at mild reaction temperatures and catalyst loadings as low as 0.1,mol,% Ir (see scheme). The excellent selectivity of the catalyst for monoalkylation of the amine function has also been exploited for the N,N,-dialkylation of diamines in both symmetric and nonsymmetric fashions. A P,N-ligand-coordinated iridium complex has been employed as an efficient catalyst for the selective monoalkylation of (hetero)aromatic amines with alcohols. A significant improvement of this alkylation method has been achieved, such that it can be performed at a temperature of 70,°C and with catalyst loadings as low as 0.1,mol,% Ir, while still affording excellent yields of secondary amines. Furthermore, the high selectivity of this catalyst for the monoalkylation of aromatic amino functions has been successfully exploited for the alkylation of diamines in both symmetric and nonsymmetric fashions, providing a novel and very efficient synthetic tool for the preparation of N,N,-dialkylated aromatic diamines. Ein P,N-Ligand-koordinierter Iridiumkomplex wird als ein effizienter Katalysator für die selektive Monoalkylierung von (hetero)aromatischen Aminen mit Alkoholen beschrieben. Eine signifikante Verbesserung dieser Alkylierungsmethode wurde erreicht. Bei Temperaturen von 70,°C und mit Katalysatorbeladungen von bis zu 0.1,mol,% Ir konnten exzellente Ausbeuten für sekundäre Amine erhalten werden. Weiterhin konnte die hohe Selektivität des Katalysators hinsichtlich der Monoalkylierung von aromatischen Aminogruppen genutzt werden, um Diamine symmetrisch und unsymmetrisch zu alkylieren. Damit steht ein neues sehr effizientes Synthesewerkzeug zur Darstellung von N,N, -alkylierten aromatischen Diaminen zur Verfügung. [source]


    Reaction of Mercury(0) with the I2 Adduct of Tetraphenyldithioimidodiphosphinic Acid (SPPh2)2NH (HL) , Crystal Structures of [Hg(HL)I2] and HgL2

    EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 23 2004
    M. Carla Aragoni
    Abstract The complex [Hg(HL)I2] (1) has been synthesised by reacting liquid Hg(0) in Et2O under mild reaction conditions with the I2 adduct of HL, HL·I2, while HgL2 (2) has been obtained from the reaction of compound 1 with HL in CH3CN. A single-crystal X-ray investigation of 1 shows four independent molecules in the asymmetric unit, each of which contains an HgII ion coordinated to two iodine atoms and two sulfur atoms of one bidentate neutral ligand in a distorted tetrahedral coordination geometry. Compound 2 consists of two anionic ligands coordinated to an HgII ion, which again displays a distorted tetrahedral coordination sphere. The reaction of 2 with HI (55 wt.-% in water) affords [Hg(HL)2](I)2 (3). Compounds 1, 2, and 3 have been characterised by FT-IR and 31P NMR spectroscopy. Density functional calculations suggest that compound 3 should feature a distorted tetrahedral coordination around the metal centre, with unequal Hg,S bond lengths. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source]


    Asymmetric Aza-Morita,Baylis,Hillman Reactions of Alkyl Vinyl Ketones with N -Protected Imines or In Situ Generated N -Protected Imines

    EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 21 2010
    Xiao-Yang Guan
    Abstract DABCO-catalyzed aza-MBH reactions of N -Boc imines with MVK and EVK have been thoroughly investigated in the paper. The asymmetric version of this aza-MBH reaction was also systematically investigated by using a chiral amine or a chiral phosphane catalyst. It was found that most of the N -protected imines are suitable substrates under the mild reaction conditions and are able to give the corresponding adducts in moderate yields with high ee values. The TQO- or LB1-catalyzed aza-MBH reactions of N -protected ,-amidoalkyl phenyl sulfones or ,-amidoalkyl p -tolyl sulfones with MVK could be well conducted, which provides a facile and direct route to obtain highly enantioselective aza-MBH adducts. The Boc protecting group of the aza-MBH product could be easily removed under acidic conditions to give the corresponding ,-methylene-,-amino ketone or ,-methylene-,-amino alcohol derivatives in good yields. [source]


    Synthesis of Triazole-Bridged Unsymmetrical Porphyrin Dyads and Porphyrin,Ferrocene Conjugates

    EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 3 2010
    Vijayendra S. Shetti
    Abstract A simple method has been used to synthesize four porphyrin azides with cores such as N4, N3S, N2SO and N2S2 in 60,90,% yields by treating the corresponding aminoporphyrins with tert -butyl nitrite (tBuONO) and azidotrimethylsilane (TMSN3) in THF/CH3CN under mild reaction conditions. The hitherto unknown aminoporphyrins with heteroatom cores were synthesized from their corresponding nitroporphyrins by standard SnCl2/HCl reduction. The azidoporphyrins were used to synthesize six triazole-bridged unsymmetrical porphyrin dyads containing two different types of porphyrin sub-units as well as five triazole-bridged porphyrin,ferrocene conjugates under CuI -catalyzed "click" reaction conditions. Various CuI -catalyzed reaction conditions were studied and the best yields of triazole-bridged dyads and conjugates were obtained with CuI/DIPEA in THF/CH3CN at room temperature for overnight. The unsymmetrical porphyrin dyads and porphyrin,ferrocene conjugates were characterized by various spectroscopic and electrochemical techniques. In unsymmetrical porphyrin dyads, the NMR, absorption and electrochemical studies indicate a weak interaction between the two porphyrin sub-units. However, preliminary photophysical studies support an efficient singlet-singlet energy transfer from one porphyrin unit to another in five unsymmetrical dyads reported here. In porphyrin,ferrocene conjugates, the fluorescence of porphyrin was quenched significantly due to photo-induced electron transfer from ferrocene to porphyrin. [source]


    Synthesis of Polysubstituted 3-Iodopyrans by Electrophilic Cyclization

    EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 14 2009
    Yong-Xin Xie
    Abstract A variety of polysubstituted 3-iodopyrans were readily prepared in good to excellent yield under mild reaction conditions by the reaction of alkynyl carboxamides with ICl, I2, and NIS. The products obtained from this process are versatile materials that can be used to construct other complex functionalized pyran structures of importance. The occurrence of the pyranyl group in both natural products and pharmaceuticals confers important value to this study. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source]


    Alcohols for the ,-Alkylation of Methyl Ketones and Indirect Aza-Wittig Reaction Promoted by Nickel Nanoparticles,

    EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 29 2008
    Francisco Alonso
    Abstract Nickel nanoparticles have been found to activate primary alcohols used for the ,-alkylation of ketones or in indirect aza-Wittig reactions. These processes involve hydrogen transfer from the alcohol to the intermediate ,,,-unsaturated ketone or imine, respectively. All these reactions are carried out in the absence of any ligand, hydrogen acceptor or base under mild reaction conditions. For the first time nickel is employed as a potential alternative to noble-metal-based catalysts in both reactions. A reaction mechanism is proposed on the basis of some deuteration experiments. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source]


    Silver-Catalyzed Incorporation of Carbon Dioxide into Propargylic Alcohols,

    EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 16 2007
    Wataru Yamada
    Abstract The combined use of a catalytic amount of silver acetate and a stoichiometric amount of DBU efficiently catalyzed the incorporation of CO2 under mild reaction conditions into a wide range of propargylic alcohols bearing a terminal or an internal triple bond to afford the corresponding cyclic carbonates in high-to-excellent yields. All the cyclic carbonates obtained from the reaction were found to be single isomers. The geometries were determined to be (Z) by X-ray crystal structure analysis and NOE experiments.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source]


    A Novel Direct Conversion of Primary Amides to Their Corresponding Methyl Esters

    EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 6 2007
    Liang-Chun Li
    Abstract A novel method was used to directly convert aliphatic and aromatic primary amides into their corresponding methyl esters in high yields (up to 99,%) under mild reaction conditions. Possible mechanisms were studied at the B3LYP/6-31++G(d,p) level of theory. Formation of the ester proceeded through a rearrangement of the ,OMe and ,NH2 groups in the RC(O)NHS(O)OMe intermediate in a H+ -catalyzed six-membered ring transition state structure. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source]


    A Convenient Synthesis of Functionalised 1-Aryl-1,3-alkadiynes

    EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 5 2005
    Irina A. Balova
    Abstract A two-step, one-pot synthesis of functionalised 1-arylalka-1,3-diynes is described. A key feature in this approach is exploitation of the "acetylene zipper" reaction to obtain terminal 1,3-alkadiynes 3 from internal isomers 1. Without isolation, but after protonation, the 1,3-alkadiynes 3 are subjected to subsequent Pd/Cu-catalyzed Sonogashira cross-couplings with aryl iodides having both electron-withdrawing and electron-donating groups. The whole sequence takes place under mild reaction conditions to afford functionalised 1-arylalka-1,3-diynes 21,35 in high yields. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source]


    Synthesis of New Tetrazole-Substituted Pyroaminoadipic and Pipecolic Acid Derivatives

    EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 2 2005
    Fatimazohra Lenda
    Abstract Racemic 5-aryl- and 5-(arylmethyl)tetrazolyl-substituted pyroaminoadipic and pipecolic acid derivatives were diastereoselectively synthesized from dimethyl meso -2,5-dibromoadipate (1) in good yields under mild reaction conditions. The key step of this reaction sequence is the selective N2 -alkylation of 5-substituted tetrazoles with 1. The reactive 2-bromo-5-tetrazolyladipate derivatives 2a,g were generated and treated with sodium azide, followed by Pd/C-catalyzed hydrogenation, to provide lactams 4a,g. The chemoselective reduction of the amide carbonyl group of 4a,g with BH3, followed by acid hydrolysis, provided 5-tetrazolylpipecolic acids in racemic form. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source]


    Highly efficient and chemoselective acetalization of carbonyl compounds catalyzed by new and reusable zirconyl triflate, ZrO(OTf)2

    HETEROATOM CHEMISTRY, Issue 3 2009
    Majid Moghadam
    Various types of aromatic aldehydes were efficiently converted to their corresponding 1,3-dioxanes and 1,3-dioxolane with 1,3-propanediol and ethylene glycol, respectively, in the presence of catalytic amount of ZrO(OTf)2 in acetonitrile at room temperature. The catalyst can be reused several times without loss of its catalytic activity. Very short reaction times, selective acetalization of aromatic aldehydes in the presence of aliphatic aldehydes and ketones, very mild reaction conditions, reusability of the catalyst, and easy workup are noteworthy advantages of this method. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:131,135, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20523 [source]


    A General Approach to the Synthesis of ,2 -Amino Acid Derivatives via Highly Efficient Catalytic Asymmetric Hydrogenation of ,-Aminomethylacrylates

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2010
    Yujuan Guo
    Abstract A new strategy was developed for the synthesis of a valuable class of ,-aminomethylacrylates via the Baylis,Hillman reaction of different aldehydes with methyl acrylate followed by acetylation of the resulting allylic alcohols and SN2,-type amination of the allylic acetates. Asymmetric hydrogenation of these diverse olefinic precursors using rhodium(Et-Duphos) catalysts provided the corresponding ,2 -amino acid derivatives with excellent enantioselectivities and exceedingly high reactivities (up to >99.5% ee and S/C=10,000). The first hydrogenation of (Z)-configurated substrates was studied for the synthesis of ,2 -amino acid derivatives. The high influence of the substrate geometry and steric hindrance on the reactivity and enantioselectivity was also disclosed for this reaction. This protocol provides a highly practical, facile and scalable method for the preparation of optically pure ,2 -amino acids and their derivatives under mild reaction conditions. [source]


    The First Anionic Thia-Fries Rearrangements at Ferrocene: Ready Access to Trifluoromethylsulfonyl-Substituted Hydroxyferrocenes and an Extremely High Interannular Stereoinduction between Cyclopentadienyl Ligands

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 8 2010
    Georg Werner
    Abstract Attempts originally directed towards the generation of ferrocyne (1,2-dehydroferrocene, 4) and ferrocenediyne (1,2,1,,2,-tetradehydroferrocene, 5) by triflate elimination from the respective ferrocenyl triflates led to the discovery of the first anionic thia-Fries rearrangements at a five-membered ring. These reactions take place with remarkable efficiency under very mild reaction conditions and yield the respective trifluoromethylsulfonyl-substituted ferrocenols. Most remarkably, the reaction starting from 1,1,-ferrocenediyl ditriflate (9) adopts an extremely high interannular stereoinduction in that exclusively the meso rearrangement product, meso -2,2,-bis(trifluoromethylsulfonyl)-1,1,-ferrocenediol (16), is formed, the corresponding racemic product 17 is not observed. It is shown that the second anionic thia-Fries rearrangement proceeds at a much larger rate than the first one. The stereochemistry and the high rate of this reaction are explained on the basis of electronic as well as steric considerations. The redox behavior of some of the unprecedented ferrocene derivatives has been characterized by cyclovoltammetry. [source]


    Facile Creation of 3-Indolyl-3-hydroxy-2-oxindoles by an Organocatalytic Enantioselective Friedel,Crafts Reaction of Indoles with Isatins

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 5 2010
    Jing Deng
    Abstract The first direct enantioselective Friedel,Crafts reaction of indoles with isatins has been developed. The process is catalyzed by simple cupreine under mild reaction conditions and affords synthetically and biologically interesting, chiral 3-indolyl-3-hydroxy-2-oxindoles in good yields (68,97%) and with high enantioselectivities (76,91%). [source]


    Copper(II) Bromide/Boron Trifluoride Etherate-Cocatalyzed Cyclization of Ketene Dithioacetals and p -Quinones: a Mild and General Approach to Polyfunctionalized Benzofurans

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 5 2010
    Yingjie Liu
    Abstract A new application of copper(II) bromide-activated ketene dithioacetals as nucleophiles in organic chemistry has been developed. Under the cocatalysis of copper(II) bromide (2.0,mol%) and boron trifluoride etherate (10,mol%), the conjugate addition and sequential cyclization of ,-electron-withdrawing group-substituted ketene dithioacetals with p -quinones in acetonitrile at room temperature gave a variety of benzofurans. This formal [3+2],cycloaddition provides a general method for catalytic synthesis of polyfunctionalized benzofurans with the advantages of readily available starting materials, cheap catalysts, mild reaction conditions, good yields and wide range of synthetic potential for the benzofuran products. Further transformations of the resulting benzofurans to 2-aminobenzofurans and benzofuro[2,3- d]pyrimidine derivatives are also investigated. [source]


    Highly Efficient One-Pot Synthesis of 2-Substituted Quinazolines and 4H -Benzo[d][1,3]oxazines via Cross Dehydrogenative Coupling using Sodium Hypochlorite

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 2-3 2010
    C. 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]


    Phase-Transfer-Catalyzed Intramolecular Cyclization of ortho -Alkynyl Phenyl Ether Derivatives for Synthesis of 2,3-Disubstituted Benzo[b]furans

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 2-3 2010
    Jie Hu
    Abstract A variety of substituted benzo[b]furans are readily prepared in good to excellent yields under the mild reaction conditions from o -(1-alkynylphenoxy)-1-phenylethanone under phase-transfer catalysis (PTC). This methodology accommodates simple experimental operations, inexpensive and environmentally benign catalysts, metal catalyst-free conditions, facile reagents and the possibility to conduct large-scale preparations. The development of carbon-carbon bond formation processes via an overall structural isomerization represents the most atom-economical approach. [source]


    The Rhodium-Catalyzed Carbene Cyclization Cycloaddition Cascade Reaction of Vinylsulfonates

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 18 2009
    Bairu Shi
    Abstract Vinylsulfonates have proved to be excellent dipolarophiles for carbonyl ylides derived from diazoketones in rhodium-catalyzed intramolecular cycloadditions. Polyfunctional substrates, such as 8 and (+)- 15, were readily available from hydroxy esters, e.g. 1 and the cyclopenta-1,3-dione 10, respectively, and the resulting polycyclic sultones were formed under mild reaction conditions in high yields with very good diastereoselectivities. A ruthenium-catalyzed asymmetric transfer hydrogenation was found to desymmetrize the meso -cyclopenta-1,3-dione 12 efficiently. [source]


    Reusable Gold(I) Catalysts with Unique Regioselectivity for Intermolecular Hydroamination of Alkynes

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 17 2009
    Antonio Leyva
    Abstract Two gold(I) phosphine complexes bearing the low-coordinating bis(trifluoromethanesulfonyl)imidate ligand, namely AuSPhosNTf2 and AuPPh3NTf2, are active catalysts for the regioselective intermolecular hydroamination of both internal and terminal alkynes under mild reaction conditions. The catalysts show a regioselectivity based on electronic rather than steric factors, which allow the preferential synthesis of regioisomers opposite to those described previously. This subtle chemo- and regioselectivity depends on the catalyst, substrates and reaction conditions employed, and allows one to perform new tandem reactions. These gold(I) complexes operate under free-solvent conditions, without exclusion of air, without addition of acidic promoters and can be quantitatively recovered and reused by simple precipitation in hexane. [source]


    Efficient Propargylation of Aldehydes and Ketones Catalyzed by Titanocene(III)

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 14-15 2009
    José Justicia
    Abstract We describe a novel method for the propargylation of a wide range of aldehydes and ketones catalyzed by titanocene(III) complexes under mild reaction conditions and compatible with many functional groups. Homopropargylic alcohols are obtained as the sole products even when ketones are used as starting materials, which is unusual in Barbier-type propargylations. [source]


    Enantio- and Diastereoselective Mannich-Type Reactions of ,-Cyano Ketones with N -Boc Aldimines Catalyzed by Chiral Bifunctional Urea

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2009
    Ju Hee Lee
    Abstract The catalytic enantioselective electrophilic Mannich-type reaction promoted by chiral bifunctional organocatalysts is described. The treatment of ,-cyano ketones with N -Boc-aldimines under mild reaction conditions afforded the corresponding ,-amino-,-cyano ketones with excellent diastereoselectivities (up to syn/anti=100/0), and excellent enantioselectivities (up to 99% ee). [source]


    Significant Self-Acceleration Effects of Nitrile Additives in the Rhodium-Catalyzed Conversion of Aldoximes to Amides: A New Mechanistic Aspect

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2009
    Min Kim
    Abstract It was found that the catalytic activity of rhodium complexes was highly sensitive to the type of N-heterocyclic carbene (NHC) ligands in the conversion of aldoximes to amides. Among those species examined, the (cyclooctadiene)rhodium chloride-carbene complex Rh(cod)(IMes)Cl exhibited the highest reactivity when it was employed in combination with a Brønsted acid, thus allowing mild reaction conditions. A significant rate acceleration effect resulting from the addition of nitrile additives was also observed. With the new protocol, the substrate scope of aldoximes has been widely expanded to include sterically congested and electronically varied derivatives. On the basis of detailed mechanistic studies, it is proposed that the reaction proceeds mainly via intramolecular electrophilic addition of aldoxime to rhodium-bound nitrile, which is different from the generally postulated two-step route: dehydration of aldoxime to nitrile followed by hydration of the latter intermediate. [source]