55 research outputs found

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    A novel strategy for the enantioselective synthesis of 3,3′-disubstituted oxindoles by the organocatalytic Michael addition of indoles to isatylidene-3-acetaldehydes was developed, which can be used for the formal total synthesis of (−)-chimonanthine and the core structure construction of (+)-gliocladin C

    Phosphine-Mediated Regio- and Stereoselective Hydrocarboxylation of Enynes

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    A phosphine-mediated regio- and stereoselective addition reaction of diverse nucleophiles to yne-enones leading to polysubstituted 1,3-diene scaffolds in moderate to good yields has been reported

    Lewis Acid-catalyzed [3 + 2]Cyclo-addition of Alkynes with <i>N</i>-Tosyl-aziridines via Carbon–Carbon Bond Cleavage: Synthesis of Highly Substituted 3-Pyrrolines

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    A novel, efficient, and highly regioselective Lewis acid-catalyzed [3 + 2] cycloaddition of alkynes with azomethine ylides, which are easily obtained from <i>N</i>-tosylaziridines via C–C bond heterolysis at room temperature was developed. Moderate enantioselectivity (70% ee) can be achieved by the application of the commercially available chiral Pybox 7 as the ligand

    Phosphine-Catalyzed Asymmetric Synthesis of α‑Quaternary Amine via Umpolung γ‑Addition of Ketimines to Allenoates

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    A first phosphine-catalyzed enantioselective umpolung γ-addition of ketimines to allenoates has been developed that provides efficient access to optically active γ,δ-unsaturated α-amino esters and δ-amino esters with a chiral tertiary stereocenter under mild conditions. The salient features of this reaction include general substrate scope, mild conditions, good yields, high enantioselectivity, ease of scale-up to gram scale, and further transformations

    Rhodium-Catalyzed Stereoselective Intramolecular Tandem Reaction of Vinyloxiranes with Alkynes: Atom- and Step-Economical Synthesis of Multifunctional Mono‑, Bi‑, and Tricyclic Compounds

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    Skeletal diversity in diversity-oriented synthesis has proven to be especially challenging. A rhodium-catalyzed intramolecular tandem reaction of vinyloxirane-alkynes leading to four structurally distinct classes of mono-, bi-, and tricyclic carbocycles and heterocycles was developed. [Rh­(NBD)<sub>2</sub>]<sup>+</sup>BF<sub>4</sub><sup>–</sup> is identified to be an efficient catalyst for these transformations. Using this highly efficient catalyst, hetero-[5 + 2] cycloadditions, tandem hetero-[5 + 2] cycloaddition/Claisen rearrangements, and subsequent cyclopropane ring-opening reactions of vinyloxiranes with monoalkynes afford 2,5-dihydrooxepins, tetrasubstituted vinylcyclopropanes, and multifunctional five-membered rings, respectively, under mild conditions with high stereoselectivity and yield. Moreover, hetero-[5 + 2] cycloaddition/Claisen rearrangement/[5 + 2] cycloaddition reactions of vinyloxiranes with diynes for step-economical construction of linearly fused 5-7-5 tricyclic skeletons has also been developed. The complete transfer of chirality from readily available vinyloxiranes to the corresponding products provides a highly efficient and practical access to these chiral cyclic compounds

    Phosphine-Mediated Regio- and Stereoselective Hydrocarboxylation of Enynes

    No full text
    A phosphine-mediated regio- and stereoselective addition reaction of diverse nucleophiles to yne-enones leading to polysubstituted 1,3-diene scaffolds in moderate to good yields has been reported

    Rhodium-Catalyzed Stereoselective Intramolecular Tandem Reaction of Vinyloxiranes with Alkynes: Atom- and Step-Economical Synthesis of Multifunctional Mono‑, Bi‑, and Tricyclic Compounds

    No full text
    Skeletal diversity in diversity-oriented synthesis has proven to be especially challenging. A rhodium-catalyzed intramolecular tandem reaction of vinyloxirane-alkynes leading to four structurally distinct classes of mono-, bi-, and tricyclic carbocycles and heterocycles was developed. [Rh­(NBD)<sub>2</sub>]<sup>+</sup>BF<sub>4</sub><sup>–</sup> is identified to be an efficient catalyst for these transformations. Using this highly efficient catalyst, hetero-[5 + 2] cycloadditions, tandem hetero-[5 + 2] cycloaddition/Claisen rearrangements, and subsequent cyclopropane ring-opening reactions of vinyloxiranes with monoalkynes afford 2,5-dihydrooxepins, tetrasubstituted vinylcyclopropanes, and multifunctional five-membered rings, respectively, under mild conditions with high stereoselectivity and yield. Moreover, hetero-[5 + 2] cycloaddition/Claisen rearrangement/[5 + 2] cycloaddition reactions of vinyloxiranes with diynes for step-economical construction of linearly fused 5-7-5 tricyclic skeletons has also been developed. The complete transfer of chirality from readily available vinyloxiranes to the corresponding products provides a highly efficient and practical access to these chiral cyclic compounds

    Rhodium-Catalyzed Stereoselective Intramolecular Tandem Reaction of Vinyloxiranes with Alkynes: Atom- and Step-Economical Synthesis of Multifunctional Mono‑, Bi‑, and Tricyclic Compounds

    No full text
    Skeletal diversity in diversity-oriented synthesis has proven to be especially challenging. A rhodium-catalyzed intramolecular tandem reaction of vinyloxirane-alkynes leading to four structurally distinct classes of mono-, bi-, and tricyclic carbocycles and heterocycles was developed. [Rh­(NBD)<sub>2</sub>]<sup>+</sup>BF<sub>4</sub><sup>–</sup> is identified to be an efficient catalyst for these transformations. Using this highly efficient catalyst, hetero-[5 + 2] cycloadditions, tandem hetero-[5 + 2] cycloaddition/Claisen rearrangements, and subsequent cyclopropane ring-opening reactions of vinyloxiranes with monoalkynes afford 2,5-dihydrooxepins, tetrasubstituted vinylcyclopropanes, and multifunctional five-membered rings, respectively, under mild conditions with high stereoselectivity and yield. Moreover, hetero-[5 + 2] cycloaddition/Claisen rearrangement/[5 + 2] cycloaddition reactions of vinyloxiranes with diynes for step-economical construction of linearly fused 5-7-5 tricyclic skeletons has also been developed. The complete transfer of chirality from readily available vinyloxiranes to the corresponding products provides a highly efficient and practical access to these chiral cyclic compounds

    Enantioselective Phosphine-Catalyzed Allylic Alkylations of <i>mix</i>-Indene with MBH Carbonates

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    The first enantioenriched synthesis of 1,1,3-trisubstituted (trifluoromethyl)­indene derivatives, bearing a quaternary stereogenic carbon center, is reported using a simple chiral sulfinamide phosphine-catalyzed asymmetric allylic alkylation of a mixture of indenes with Morita–Baylis–Hillman carbonates. The resulting derivatives can serve as a valuable synthetic building block for some drugs and natural products. Broad substrate scope and high regio- and enantioselectivity of this reaction were particularly remarkable

    Enantioselective Phosphine-Catalyzed Allylic Alkylations of <i>mix</i>-Indene with MBH Carbonates

    No full text
    The first enantioenriched synthesis of 1,1,3-trisubstituted (trifluoromethyl)­indene derivatives, bearing a quaternary stereogenic carbon center, is reported using a simple chiral sulfinamide phosphine-catalyzed asymmetric allylic alkylation of a mixture of indenes with Morita–Baylis–Hillman carbonates. The resulting derivatives can serve as a valuable synthetic building block for some drugs and natural products. Broad substrate scope and high regio- and enantioselectivity of this reaction were particularly remarkable
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