Alkylation

Distribution by Scientific Domains
Distribution within Chemistry

Kinds of Alkylation

  • Palladium-Catalyze asymmetric allylic alkylation
  • allylic alkylation
  • asymmetric alkylation
  • asymmetric allylic alkylation
  • catalytic alkylation
  • catalytic asymmetric alkylation
  • craft alkylation
  • diastereoselective alkylation
  • direct alkylation
  • enantioselective alkylation
  • intramolecular alkylation
  • reductive alkylation

  • Terms modified by Alkylation

  • alkylation damage
  • alkylation process
  • alkylation reaction
  • alkylation step

  • Selected Abstracts


    Preferred Phosphorus Ylide Formation Upon Alkylation of Lithiobis(diphenylphosphanyl)acetonitrile,

    EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 19 2007
    Leonie Braun
    Abstract Deprotonation of the readily available chelate phosphane bis(diphenylphosphanyl)acetonitrile (6) leads to stabilized carbanion system 7. Lithiobis(diphenylphosphanyl)acetonitrile (7) features a unique thf-stabilized monomeric structure in the crystal form with a short cyanonitrogen,Li contact. Alkylation of 7 with n -alkyl bromides (R,Br, R = ethyl, n -propyl, n -butyl, n -hexyl) takes place selectively at one phosphorus atom to yield stabilized ylides 8a,d (two examples characterized by X-ray diffraction). Treatment of 7 with the more reactive alkylation agents methyl iodide or benzyl bromide results in alkylation at both phosphorus atoms to give delocalized bis(phosphonium)ylides 9a,b (both characterized by X-ray diffraction). Similarly, the reaction of 7 with 1,3-dibromopropane or 1,4-dibromobutane yields six- and seven-membered heterocyclic bis(phosphonium)ylides 10a,b, respectively. The spectroscopic characterization and X-ray crystal structure analysis again indicate the presence of delocalized Ph2RP,C(CN),PRPh2 substructures. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source]


    Electro-Organocatalysis: Enantioselective ,-Alkylation of Aldehydes

    EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 23 2010
    Xuan-Huong Ho
    Abstract The asymmetric organocatalyzed ,-alkylation of aldehydes via a cationic radical enamine intermediate was performed under environmentally benign electro-oxidation conditions without the use of chemical oxidants. To promote the desired ,-alkylation reaction of aldehydes, various aldehydes with xanthene or cycloheptatriene groups were exposed to electro-organocatalytic conditions to afford optically active ,-substituted aldehydes (,-alkylated aldehydes) in good yield. A reaction mechanism involving the cationic radical enamine was proposed based on the cyclic voltammetry (CV) results, DFT calculations, and control experiments. [source]


    Supported Chiral Monodentate Ligands in Rhodium-Catalysed Asymmetric Hydrogenation and Palladium-Catalysed Asymmetric Allylic Alkylation

    EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 33 2009
    Bert H. G. Swennenhuis
    Abstract A family of monodentate polystyrene-supported phosphites, phosphoramidites and phosphanes has been prepared and evaluated as ligands in rhodium-catalysed asymmetric hydrogenation and palladium-catalysed asymmetric allylic alkylation. The supported ligands yielded active and enantioselective catalysts, which in selected cases match the performance of the nonsupported counterparts. As expected, the performance of the supported ligands in the rhodium-catalysed hydrogenation depends on the nature of the ligand, the type of polymeric support, as well as on the substrate. Additionally, the supported ligands have been applied in the monodentate ligand combination approach, by combining them with nonsupported monodentate ligands. The partially supported heteroligand combinations possess different catalytic properties than the related nonsupported combinations. The heteroligand species, however, are not formed selectively, and nonsupported homoleptic complexes also contribute to the overall activity. (© 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]


    Catalytic Asymmetric Alkylation of Aldehydes by Using Trialkylboranes

    EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 26 2008
    Takahiro Ukon
    Abstract Triethylborane can be used in the asymmetric alkylation of aldehydes by using a 3-(3,5-diphenylphenyl)-H8 -BINOL-derived titanium(IV) catalyst in the presence of an excess amount of titanium tetraisopropoxide. The reaction proceeds with a low catalyst loading (2 mol-%), exhibiting high enantioselectivity for aromatic and unsaturated aldehydes. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source]


    Transition-Metal-Free Synthesis of Perdeuterated Imidazolium Ionic Liquids by Alkylation and H/D Exchange

    EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 17 2008
    Ralf Giernoth
    Abstract Economic, transition-metal-free syntheses of partially or completely deuterated imidazolium ionic liquids (ILs) were developed. Double alkylation starting from imidazole afforded side-chain deuterated imidazolium ionic liquids, which subsequently were fully deuterated by H/D-exchange on the cation ring. Isotopic exchange was studied for a range of ionic liquids, solvents and bases. Here, the presence of small amounts of basic impurities was found to significantly affect the exchange behaviour.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source]


    Conformationally Biased Selective Alkylation of trans -Cyclohexane-1,2-bis(sulfonamide) Assisted by Solvent-Tuned Protecting Groups: Applications to the Synthesis of a Large Optically Active Polyazamacrocycle,

    EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 17 2006
    Carmen Peña
    Abstract The selective alkylation of (R,R)-cyclohexane-1,2-bis(sulfonamide) with trityl bromoalkyl ethers has been studied in detail. The major formation of either mono- or dialkylated compounds clearly depends on the right combination of protecting groups and the reaction solvent. An exhaustive study suggests that this effect can be reasonably explained by the conformational preferences of the monoalkylated compounds, which also depend on the reaction medium, solvophobic effects and weak intramolecular interactions. Structural analysis by NOE measurements showed the presence of folded conformations in solution for all the tested examples. Monte Carlo conformational searches supported this proposal, showing a very good correlation between the fraction of folded species and the selectivity towards monoalkylation. Finally, tuning of the reaction conditions, leading to either extended or folded conformations of the monoalkylated synthetic intermediates, was exploited for the efficient synthesis of a large optically active polyazamacrocycle. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source]


    Diastereoselective Alkylation of (Arene)tricarbonylchromium and Ferrocene Complexes Using a Chiral, C2 -Symmetrical 1,2-Diamine as Auxiliary

    EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 15 2006
    Alexandre Alexakis
    No abstract is available for this article. [source]


    Diastereoselective Alkylation of (Arene)tricarbonylchromium and Ferrocene Complexes Using a Chiral, C2 -Symmetrical 1,2-Diamine as Auxiliary

    EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 7 2005
    Alexandre Alexakis
    Abstract The aminal of (benzaldehyde)tricarbonylchromium and en-antiopure bipyrrolidine undergoes diastereoselective ortho -metallation with butyllithium. Quenching with various electrophiles, followed by hydrolysis of the aminal, affords ortho -substituted (benzaldehyde)tricarbonylchromium compounds with high ee (91,99,%). When quenched with Ph2PCl, a new chiral P,N-bidentate ligand is obtained, which shows efficiency in Pd- and Cu-catalysed reactions. The aminal of ferrocenecarbaldehyde could also be formed, but the ortho -deprotonation occurs with only moderate diastereoselectivity (70,%). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source]


    Double Cyclization of Bis(,-hetarylmethyl)amino Esters to Optically Active Bridged N-Heterocycles of HIV-Inhibiting Activity

    EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 16 2004
    Heike Faltz
    Abstract Anellated 1-azabicyclo[3.3.1]nonanes 6 were synthesized by several routes starting from natural ,-amino esters 2 and o -haloaryl- or o -bromohetarylmethyl bromides 1. N -Alkylation of the starting amino esters to 5 and 3 was followed by halogen/lithium exchange and double cyclization. The cyclization products 6 exhibit interesting inhibition of RNase H and DNA-polymerase activity of reverse transcriptase (RT) of HIV-1 at concentrations where human cellular DNA polymerases are not affected. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source]


    Highly Enantioselective Synthesis of No-Carrier-Added 6-[18F]Fluoro- L -dopa by Chiral Phase-Transfer Alkylation

    EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 13 2004
    Christian Lemaire
    Abstract [18F]Fluoro- L -dopa, an important radiopharmaceutical for positron emission tomography (PET), has been synthesized using a phase-transfer alkylation reaction. A chiral quaternary ammonium salt derived from a Cinchona alkaloid served as phase-transfer catalyst for the enantioselective alkylation of a glycine derivative. The active methylene group of this Schiff-base substrate was deprotonated with cesium hydroxide and rapidly alkylated by the 2-[18F]fluoro-4,5-dimethoxybenzyl halide (X = Br, I). The reaction proceeded with high yield (> 90%) at 0 °C or room temperature in various solvents such as toluene or dichloromethane. Preparation of the [18F]alkylating agent on a solid support was developed. After labelling, the labeled [18F]fluoroveratraldehyde was trapped on a tC18 cartridge and then converted on the cartridge into the corresponding benzyl halide derivatives by addition of aqueous sodium borohydride and gaseous hydrobromic or -iodic acid. Hydrolysis and purification by preparative HPLC made 6-[18F]fluoro- L -dopa ready for human injection in a 25,30% decay-corrected radiochemical yield in a synthesis time of 100 min. The product was found to be chemically, radiochemically and enantiomerically pure (ee > 95%). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source]


    Novel Cyclic 1,2-Diacetals Derived from (2R,3R)-(+)-Tartaric Acid: Synthesis and Application as N,O Ligands for the Enantioselective Alkylation of Benzaldehyde by Diethylzinc

    EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 8 2004
    M. Teresa Barros
    Abstract A chiral cyclic 1,2-diacetal derived from tartaric acid was used as the basic structural unit for novel ligands. Monooxazoline carbinols in which the degree of substitution of the alcohol and the nature of the stereocentre in the oxazoline ring were varied were synthesized in moderate to good yields. The influence of these structural factors on asymmetric induction was examined in the enantioselective addition of diethylzinc to benzaldehyde. Up to 60% ee was observed with a secondary or a tertiary alcohol as the metal-chelating group. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source]


    Domino Aza-Claisen/Mannich Cyclization Reaction from a Chiral ,-Alkoxy Enamine or Sequential Alkylation of an ,-Alkoxy Ester Enolate or Nitrile Anion, Followed by an Intramolecular Wittig Reaction: Two (3+2) Annulation Routes to Homochiral 4-Alkyl-4-hydroxy-2-cyclopentenone Synthesis

    EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 14 2003
    Cyrille Kuhn
    Abstract A study on the enantioselective synthesis of 4-alkyl-4-hydroxyalkylidene-cyclopentenone prostaglandins is reported. Two (3+2) annulation processes allow the synthesis of homochiral 4-alkyl-4-hydroxy-2-cyclopentenones 4,5, 10,11, and 17. The first process involves a domino aza-Claisen/Mannich cyclization reaction, resulting from the alkylation of an ,-alkoxy-enamine, derived from chiral ,-alkoxy aldehydes 1, 9, or 16 with 3-iodo-2-(methoxymethoxy)prop-1-ene (3) as the acetonyl equivalent. The second process is based on the sequential alkylation of esters 21, 39, or nitrile 20 with acetonyl equivalents 3 or 25, followed by an intramolecular Wittig reaction. As an application, the synthesis of the naturally occurring alkylidene-cyclopentenone prostaglandin clavulone II from the spiro[cyclopentene-furan]one 5 and the formal total synthesis of (+/-)-untenone 19 has been carried out. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source]


    Synthesis and Optoelectronic Properties of Nonpolar Polyrotaxane Insulated Molecular Wires with High Solubility in Organic Solvents,

    ADVANCED FUNCTIONAL MATERIALS, Issue 21 2008
    Michael J. Frampton
    Abstract Hydrophilic polyanionic conjugated polyrotaxanes are readily synthesized in water by Suzuki coupling, but their high polarity and ionic nature limit the potential applications of these materials. Here, we demonstrate three methods for transforming these polar polyelectrolytes into nonpolar lipophilic insulated molecular wires. A water-soluble polyfluorene- alt -biphenylene ,-cyclodextrin (CD) polyrotaxane was converted into nonpolar derivatives by methylation of the carboxylic acid groups with diazomethane and conversion of the hydroxyl groups of the CDs to benzyl ethers, trihexylsilyl ethers, benzoyl esters, and butanoate esters to yield polyrotaxanes that are soluble in organic solvents such as chloroform and cyclohexane. Elemental analysis, NMR spectroscopy, and gel permeation chromatography (GPC) data support the proposed structures of the organic-soluble polyrotaxanes. The extents of reaction of the polyrotaxane CD hydroxyl groups were 55% for trihexylsilyl chloride/imidazole; 81% for benzyl chloride/sodium hydride; 72% for benzoyl chloride/pyridine/4-dimethylaminopyridine; and 98% butanoic anhydride/pyridine/4-dimethylaminopyridine. Alkylation, silylation, and esterification increase the bulk of the encapsulating sheath, preventing interstrand aggregation, increasing the photoluminescence efficiency in the solid state and simplifying the time-resolved fluorescence decay. The organic-soluble polyrotaxanes were processed into polymer light-emitting diodes (PLEDs) from solution in nonpolar organic solvents, thereby excluding ionic impurities from the active layer. [source]


    Synthesis of Novel Chiral Ionic Liquids and Their Phase Behavior in Mixtures with Smectic and Nematic Liquid Crystals

    HELVETICA CHIMICA ACTA, Issue 11 2004
    Martin Tosoni
    Alkylation of 1-alkyl-1H -imidazoles 2a,f with citronellyl bromide 1b opens access to chiral 1H -imidazolium bromides 3a,f (Scheme,1). A similar strategy yielded the chiral pyridinium ionic liquid 6 (Scheme,2). Dialkylation of 1H -imidazole (7) gave the C2 -symmetric 1,3-dicitronellyl-1H -imidazolium bromide (8) (Scheme,3). Differential scanning calorimetry and optical polarizing microscopy revealed smectic mesophases for 1-citronellyl-3-tetradecy-1H -limidazolium bromide (3e) and 1-citronellylpyridinium bromide (6) (Table). In binary mixtures with smectic and nematic liquid crystals 9 and 10, 1-citronellyl-3-methyl-1H -imidazolium bromide (3a) behaved differently. Increasing quantities of 3a cause a decrease of the smectic-phase width for the mixture 3a/9 (Fig.,3), whereas the phase width of the nematic phase for 3a/10 remained nearly constant (Fig.,4). [source]


    Enantioselective Copper-Catalysed Allylic Alkylation of Cinnamyl Chlorides by Grignard Reagents using Chiral Phosphine-Phosphite Ligands

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2010
    Wibke Lölsberg
    Abstract The copper(I)-catalysed SN2,-type allylic substitution of E -3-aryl-allyl chlorides (cinnamyl chlorides) using Grignard reagents represents a powerful method for the synthesis of compounds carrying a benzylic stereocentre. By screening a small library of modular chiral phosphine-phosphite ligands a new copper(I)-based catalyst system was identified which allows the performance of such reactions with exceptional high degrees of regio- and enantioselectivity. Best results were obtained using TADDOL-derived ligands (3,mol%), copper(I) bromide,dimethyl sulfide (CuBr,SMe2) (2.5,mol%) and methyl tert -butyl ether (MTBE) as a solvent. Various (1-alkyl-allyl)benzene derivatives were prepared with up to 99% ee (GC) in isolated yields of up to 99%. In most cases the product contained less than 3% of the linear regioisomer (except for ortho -substituted substrates). Both electron-rich and electron-deficient cinnamyl chlorides were successfully employed. The absolute configuration of the products was assigned by comparison of experimental and calculated CD spectra. The substrates were prepared from the corresponding alcohols by reaction with thionyl chloride. Initially formed mixtures of regioisomeric allylic chlorides were homogenised by treatment with CuBr,SMe2 (2.5,mol%) in the presence of triphenyl phosphine (PPh3) (3,mol%) in MTBE at low temperature to give the pure linear isomers. In reactions with methylmagnesium bromide (MeMgBr) an ortho -diphenylphosphanyl-arylphosphite ligand with an additional phenyl substituent in ortho, -position at the aryl backbone proved to be superior. In contrast, best results were obtained in the case of higher alkyl Grignard reagents (such as ethyl-, n -butyl-, isopropyl-, and 3-butenylmagnesium bromides) with a related ligand carrying an isopropyl substituent in ortho, -position. The method was tested on a multi-mmol scale and is suited for application in natural product synthesis. [source]


    Phase-Transfer-Catalyzed Olefin Isomerization/,-Alkylation of ,-Alkynylcrotonates as a Route for 1,4-Enynes

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2010
    Takuya Hashimoto
    Abstract The phase-transfer-catalyzed alkylation of ,-alkynylcrotonates was developed as a means to provide 1,4-enynes deconjugated by an all-carbon quaternary center. Extension to the asymmetric version using the chiral phase-transfer catalyst (S)- 3 provided the alkylated compounds with up to 87% ee. [source]


    Enantioselective Organocatalytic Synthesis of Arylglycines via Friedel,Crafts Alkylation of Arenes with a Glyoxylate Imine

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2010
    Dieter Enders
    Abstract The enantioselective organocatalytic synthesis of arylglycines has been developed employing 1,mol% of an enantiopure N -triflyl phosphoramide Brønsted acid as organocatalyst. Various differently substituted phenylglycine derivatives can be synthesized in good to excellent yields and enantiomeric excesses based on a Friedel,Crafts alkylation of electron-rich arenes with a glyoxylate imine. A novel protocol for the deprotection of the N - tert -butylsulfonyl (Bus) group has also been developed. [source]


    Dual Amine- and Brønsted Acid-Catalyzed ,-Allylic Alkylation of Aldehydes

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2010
    Li-Wen Xu
    Abstract A very simple method was developed for the direct, palladium-free catalytic ,-allylic alkylation of aldehydes. The direct organocatalytic intermolecular ,-allylic alkylation reaction was mediated by a simple combination of Brønsted acid and enamine catalysis which furnished ,-allylic alkylated aldehydes and cyclohexanone in high yields and chemoselectivities. The reaction conditions are mild and environmental friendly, the process is conducted under an atmosphere of air without the need for dried solvents, and water is the only side product of the allylic alkylation reaction. [source]


    Development of Diphenylamine-Linked Bis(imidazoline) Ligands and Their Application in Asymmetric Friedel,Crafts Alkylation of Indole Derivatives with Nitroalkenes

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 7 2010
    Han Liu
    Abstract The new diphenylamine-linked bis(imidazoline) ligands were prepared through Kelly-You's imidazoline formation procedure mediated by Hendrickson's reagent in good yields. The novel ligands were tested in the asymmetric Friedel,Crafts alkylation of indole derivatives with nitroalkenes. In most cases, good yields (up to 97%) and excellent enantioselectivities (up to 98%) can be achieved. The optimized bis(imidazoline) ligand with trans -diphenyl substitution on the imidazoline ring gave better enantioselectivity than the corresponding bis(oxazoline) ligand. [source]


    Copper-Catalyzed Asymmetric Allylic Alkylation of Halocrotonates: Efficient Synthesis of Versatile Chiral Multifunctional Building Blocks

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 6 2010
    Hartog, Tim den
    Abstract The highly enantioselective synthesis of ,-methyl-substituted esters is reported in up to 90% yield and up to 99% ee using copper-TaniaPhos as chiral catalyst. The transformation proved scalable to at least 6.6,mmol (1.7,g scale). The products of this transformation have been further elaborated to multifunctional building blocks with a single (branched esters and acids) or multiple stereogenic centers (vicinal dimethyl esters, as well as, hydroxy- or iodo-substituted lactones). [source]


    One-Pot Three-Step Synthesis of Naphtho[2,3- a]carbazole- 5,13-diones using a Tandem Radical Alkylation,Cyclization, Aromatization Reaction Sequence

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 5 2010
    Chunyong Ding
    Abstract A three-step, one-pot tandem reaction including radical nucleophilic alkylation/cyclization/aromatization was developed using 0.3 equivalents of silver(I) acetate (AgOAc) as the catalyst and 2 equivalents of ammonium persulfate [(NH4)2S2O8] as the oxidant. This strategy is highly efficient for the assembly of pentacyclic complex carbazoles from aryl-fused bromobenzoquinones and indol-3-ylpropanoic acid acids in 52,72% overall yields (three steps). This new approach provides a significant improvement over the previously reported methods and would greatly facilitate analog library construction of pentacyclic complex carbazoles and benefit further biological evaluation of these compounds. [source]


    Copper-Catalyzed Asymmetric Allylic Alkylation of Racemic Cyclic Substrates: Application of Dynamic Kinetic Asymmetric Transformation (DYKAT)

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 2-3 2010
    Jean-Baptiste Langlois
    Abstract The copper-catalyzed asymmetric allylic alkylation (AAA) is of great interest in organic synthesis. This reaction was extensively studied using a broad range of substrates, ligands and organometallic reagents. However, the use of racemic substrates was still limited. Although some processes of kinetic resolution are reported in the literature, no examples of quantitative deracemization are described as is the case for the Pd-catalyzed allylic alkylation. We present here a full account of our investigations through the development of the first example of such a process in copper-catalyzed AAA. High enantioselectivities (up to 99% ee), scope of the reaction and mechanistic considerations are reported herein. [source]


    Synthesis of Selectively Mono-N-Arylated Aliphatic Diamines via Iridium-Catalyzed Amine Alkylation

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 17 2009
    Benoît Blank
    Abstract A highly selective phosphorus/nitrogen (P,N) ligand-based iridium catalyst system efficiently catalyzes the reaction of arylamines with unprotected amino alcohols, yielding N-arylated aliphatic diamines in yields of up to 93%. The reaction can be performed with a wide variety of branched and linear amino alcohols in combination with various aminopyridines or substituted anilines. [source]


    Copper-Catalyzed N -Alkylation of Sulfonamides with Benzylic Alcohols: Catalysis and Mechanistic Studies

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 17 2009
    Xinjiang Cui
    Abstract The N -alkylation of sulfonamides with alcohols is efficiently performed in the presence of easily available copper catalysts via hydrogen borrowing methodology. Applying a copper acetate/potassium carbonate system the reaction of sulfonamides and alcohols gave the corresponding secondary amines in excellent yield. In situ HR-MS analysis indicated that bissulfonylated amines are formed under air atmosphere, which act as self-stabilizing ligands for the catalytic system. UV-visible measurements suggest the interaction between the copper centre and the bissulfonylated amine. Reactions of benzyl alcohol- d7 with p -toluenesulfonamide, N -benzyl- p -toluenesulfonamide or N -benzylidenetoluenesulfonamide revealed that the reaction proceeds via a transfer hydrogenation mechanism and the whole process is micro-reversible. Competitive reactions of benzyl alcohol and benzyl alcohol- d7 with p -toluenesulfonamide revealed a kinetic isotope effect (kH/kD) of 3.287 (0.192) for the dehydrogenation of benzyl alcohol and 0.611 (0.033) for the hydrogenation of the N -benzylidene- p -toluenesulfonamide intermediate, which suggests that dehydrogenation of the alcohol is the rate-determining step. [source]


    Synthesis of Functionalized Indoles with an ,-Stereogenic Ketone Moiety Through an Enantioselective Friedel,Crafts Alkylation with (E)-1,4-Diaryl-2-butene-1,4-diones

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 14-15 2009
    Gonzalo Blay
    Abstract Chiral complexes of BINOL-based ligands with hafnium tert -butoxide catalyze the enantioselective Friedel,Crafts alkylation of indoles with (E)-1,4-diaryl-2-butene-1,4-diones at room temperature, with good yields and ee up to 94%. Hafnium(IV) was found to be a more effective Lewis acid than other frequently used metal ions such as titanium(IV) or zirconium(IV). Unlike the enantioselective Friedel,Crafts alkylation of indoles with ,,,-unsaturated compounds where the stereogenic center is generated in the ,-position to a carbonyl group, the Friedel,Crafts alkylation with 2-butene-1,4-diones described here generates an ,-stereogenic center with respect to one of the carbonyl groups. This can be regarded as an inversion of the normal reactivity pattern or umpolung. The enantioselective Friedel,Crafts alkylation of indoles with (E)-4-oxo-4-phenylbutenoates using a zirconium(IV)-BINOL catalyst is also reported. This reaction takes place regioselectively at the carbon in the ,-position to the ketone carbonyl group, generating an ,-ester stereogenic center. [source]


    Iron(III)-Catalyzed Intramolecular Friedel,Crafts Alkylation of Electron-Deficient Arenes with ,-Activated Alcohols

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 14-15 2009
    Marco Bandini
    Abstract "Deficient" but "efficient", the first example of a catalytic Friedel,Crafts alkylation of arenes, carrying electron-withdrawing groups, with alcohols is reported. The optimized iron(III) chloride (97%) catalyzed allylation, benzylation and propargylation procedures open an access to a range of tetrahydronaphthalenes, tetrahydroisoquinolines and tetrahydrobenzo[d]azepines featuring tertiary benzylic stereocenters in excellent yields (up to 92%) and short reaction times. [source]


    Palladium-Catalyzed Asymmetric Allylic Alkylation of 2,3-Allenyl Acetates Using a Chiral Diaminophosphine Oxide

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2009
    Tetsuhiro Nemoto
    Abstract An enantioselective synthesis of allenes through palladium-catalyzed asymmetric allylic alkylation using a chiral diaminophosphine oxide is described. The asymmetric allylic alkylations proceeded in the presence of a catalytic amount of lithium acetate at 4,°C, affording the chiral allenes in excellent yield with up to 99% ee. [source]


    An Efficient Enantioselective Method for Asymmetric Friedel,Crafts Alkylation of Indoles with ,,,-Unsaturated Aldehydes

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 5 2009
    Liang Hong
    Abstract The Lewis base-Lewis base bifunctional catalytic system has been developed and successfully applied to the asymmetric Friedel,Crafts alkylation of indoles with ,,,-unsaturated aldehydes. The reactions are promoted by chiral diphenylprolinol trimethylsilyl ether in the presence of triethylamine. By this protocol, optically active 3-substituted indoles can be obtained in an organocatalytic process that is free of Lewis or protic acid in high yields with up to 98% ee. Besides, this reaction could be carried out on a gram scale without any loss in the enantioselectivity. [source]


    Ligand-Free Silver(I)-Catalyzed Intramolecular Friedel,Crafts Alkylation of Arenes with Allylic Alcohols

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 3 2009
    Marco Bandini
    Abstract The silver-catalyzed direct activation of allylic alcohols as electrophilic partners for intramolecular Friedel,Crafts alkylation of arenes is described. Use of silver triflate (AgOTf; 10 mol%) enabled functionalized 1-vinyl-1,2,3,4-tetrahydronaphthalenes and a 4-vinyl-1,2,3,4-tetrahydroisoquinoline to be isolated in good yields with high levels of regiochemistry, under a ligand-free regime. [source]