27 research outputs found

    Asymmetric Michael Addition of Ketones to Alkylidene Malonates and Allylidene Malonates via Enamineā€“Metal Lewis Acid Bifunctional Catalysis

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    Novel enamineā€“metal Lewis acid bifunctional catalysts were successfully applied to the asymmetric Michael addition of ketones to alkylidene malonates, offering excellent stereoselectivity (up to >99% <i>ee</i> and >99:1 <i>dr</i>). The asymmetric Michael addition of ketones to allylidene malonates was also achieved

    Asymmetric Michael Addition of Ketones to Alkylidene Malonates and Allylidene Malonates via Enamineā€“Metal Lewis Acid Bifunctional Catalysis

    No full text
    Novel enamineā€“metal Lewis acid bifunctional catalysts were successfully applied to the asymmetric Michael addition of ketones to alkylidene malonates, offering excellent stereoselectivity (up to >99% <i>ee</i> and >99:1 <i>dr</i>). The asymmetric Michael addition of ketones to allylidene malonates was also achieved

    Cu-Catalyzed Three-Component Coupling of Aryne, Alkyne, and Benzenesulfonothioate: Modular Synthesis of <i>o</i>ā€‘Alkynyl Arylsulfides

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    A copper-catalyzed three-component coupling reaction of in situ formed arynes, terminal alkynes, and benzenesulfonothioates is described. This reaction provides an efficient modular synthesis of <i>o</i>-alkynyl arylsulfides from easily available starting materials. This process involves one Cā€“S bond and one Cā€“C bond formation in one pot

    Atom Transfer Radical Addition to Alkynes and Enynes: A Versatile Gold/Photoredox Approach to Thio-Functionalized Vinylsulfones

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    An efficient intermolecular atom-transfer addition reaction of alkynes via the combination of visible-light photoredox catalysis and gold catalysis has been developed, affording diverse trifluoromethylthio- and difluoromethylthio-functionalized vinylsulfones with high stereoselectivity in good yields. Thiosulfonylation reaction of enyne can also be realized for constructing functionalized carbo- and heterocycles through a radical cascade cyclization process. These reactions proceed through a gold-assisted sulfonyl radical addition pathway

    Copper-Catalyzed Oxidative Trifunctionalization of Olefins: An Access to Functionalized Ī²ā€‘Keto Thiosulfones

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    Aerobic oxidative trifunctionalization of olefins for the synthesis of functionalized Ī²-keto thiosulfones has been described. The transformation proceeds through molecular oxygen activation under copper catalysis and forms the two new Cā€“S bonds in a single operation using mild conditions. A novel Cu-catalyzed sulfonyl radical addition/oxidation/funtionalization relay mechanism was proposed for the discovered reaction

    Atom Transfer Radical Addition to Alkynes and Enynes: A Versatile Gold/Photoredox Approach to Thio-Functionalized Vinylsulfones

    No full text
    An efficient intermolecular atom-transfer addition reaction of alkynes via the combination of visible-light photoredox catalysis and gold catalysis has been developed, affording diverse trifluoromethylthio- and difluoromethylthio-functionalized vinylsulfones with high stereoselectivity in good yields. Thiosulfonylation reaction of enyne can also be realized for constructing functionalized carbo- and heterocycles through a radical cascade cyclization process. These reactions proceed through a gold-assisted sulfonyl radical addition pathway

    In Situ Construction of Three Anion-Dependent Cu(I) Coordination Networks as Promising Heterogeneous Catalysts for Azideā€“Alkyne ā€œClickā€ Reactions

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    Three CuĀ­(I) coordination networks, namely, {[Cu<sub>2</sub>(bpz)<sub>2</sub>Ā­(CN)Ā­X]Ā·CH<sub>3</sub>CN}<sub><i>n</i></sub>, (X = Cl, <b>1</b>; I, <b>3</b>), {[Cu<sub>6</sub>(bpz)<sub>6</sub>Ā­(CH<sub>3</sub>CN)<sub>3</sub>Ā­(CN)<sub>3</sub>Br]Ā·2OHĀ·14CH<sub>3</sub>CN}<sub><i>n</i></sub>, (<b>2</b>, bpz = 3,3ā€²,5,5ā€²-tetramethyl-4,4ā€²-bipyrazole), were prepared by using solvothermal method. The cyanide ligands in these networks were generated in situ by cleavage of Cā€“C bond of MeCN under solvothermal condition. The structures of these networks are dependent on halogen anions. Complex <b>1</b> is a ladderlike structure with Ī¼<sub>2</sub>-CN<sup>ā€“</sup> as rung and Ī¼<sub>2</sub>-bpz as armrest. The Cl<sup>ā€“</sup> in <b>1</b> is at terminal position but does not extend the one-dimensional (1D) ladder to higher dimensionalities. Complex <b>2</b> is a three-dimensional (3D) framework comprised of novel planar [Cu<sub>3</sub>Br] triangle and single Cu nodes, which are extended by Ī¼<sub>2</sub>-bpz and Ī¼<sub>2</sub>-CN<sup>ā€“</sup> to form a novel (3,9)-connected <b>gfy</b> network. Density functional theory calculations showed that single-electron delocalization of Br atom induces the plane structure of [Cu<sub>3</sub>Br]. Complex <b>3</b> also possesses a similar ladderlike subunit as in <b>1</b>, but the I<sup>ā€“</sup> acts as bidentate bridge to extend the ladder to 3D framework with a four-connected <b>sra</b> topology. The three networks show notable catalytic activity on the click reaction. The compared catalytic results demonstrate that complex <b>2</b> possesses the best catalysis performance among three complexes, which is ascribed to the largest solvent-accessible void (porosity: <b>2</b> (29.4%) > <b>1</b> (25.7%) > <b>3</b> (17.6%)) and the more CuĀ­(I) active sites in <b>2</b>. The present combined structureā€“property studies provide not only a new synthetic route to obtain a new kind of catalyst for click reaction but also the new insights on catalyst structureā€“function relationships

    Copper(I)-Catalyzed Three-Component Click/Persulfuration Cascade: Regioselective Synthesis of Triazole Disulfides

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    A copperĀ­(I)-catalyzed three-component CuAAC/persulfuration reaction providing rapid access to asymmetric triazole disulfides has been developed. The interrupted click reaction shows broad substrate scope, complete regioselectivity, and excellent functional group tolerability

    Copper(I)-Catalyzed Three-Component Click/Alkynylation: One-Pot Synthesis of 5ā€‘Alkynyl-1,2,3-triazoles

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    A copperĀ­(I)-catalyzed tandem CuAAC/alkynylation reaction of various alkynes, organic azides, and bromoalkynes to provide rapid access to 5-alkynyl-1,2,3-triazoles has been developed. The reaction proceeded via a copper-catalyzed alkyne azide cycloaddition followed by interception of the in situ formed cuprateā€“triazole intermediate with bromoalkyne. This reaction offers a new method to afford fully substituted triazoles in high yields with complete regioselectivity under mild reaction conditions
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