26 research outputs found

    Palladium-Catalyzed Three-Component Cross-Coupling of Conjugated Dienes with Indoles Using Ethynylbenziodazolones as Electrophilic Alkynylating Reagents

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    A palladium-catalyzed regioselective 1,2-alkynyl-carbonalization of conjugated dienes with ethynylbenziodazolone (EBZ) and indoles has been developed for the first time. Various molecules containing alkenyl, alkynyl, and indole groups were readily obtained. Moreover, the resulting products can be applied to various derivatizations. This protocol uses EBZ as an electrophilic alkynylating reagent, avoiding the byproduct of dimerization of alkynes

    Catalytic Enantioselective Intermolecular Three-Component Sulfenylative Difunctionalizations of 1,3-Dienes

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    This work demonstrates regio- and enantioselective intermolecular three-component oxysulfenylations of 1,3-dienes with alcohols, phenols, acids, and water as O-nucleophiles. These reactions were enabled by the cooperative catalysis of chiral sulfide and phosphoric acid. Various useful sulfur-containing allylic ethers, allylic esters, and allylic alcohols were readily obtained in moderate to excellent yields with high to excellent enantioselectivities and excellent regioselectivities. This protocol provides high chemo-, regio-, and enantioselectivities together with a broad scope and good functional group compatibility

    Catalytic Enantioselective Intermolecular Three-Component Sulfenylative Difunctionalizations of 1,3-Dienes

    No full text
    This work demonstrates regio- and enantioselective intermolecular three-component oxysulfenylations of 1,3-dienes with alcohols, phenols, acids, and water as O-nucleophiles. These reactions were enabled by the cooperative catalysis of chiral sulfide and phosphoric acid. Various useful sulfur-containing allylic ethers, allylic esters, and allylic alcohols were readily obtained in moderate to excellent yields with high to excellent enantioselectivities and excellent regioselectivities. This protocol provides high chemo-, regio-, and enantioselectivities together with a broad scope and good functional group compatibility

    Total Synthesis of (±)-Maistemonine, (±)-Stemonamide, and (±)-Isomaistemonine

    No full text
    A full account of the total synthesis of (±)-maistemonine, (±)-stemonamide, and (±)-isomaistemonine is presented. Two approaches have been developed to construct the basic pyrrolo­[1,2-a]­azepine core of the Stemona alkaloids, featuring a tandem semipinacol/Schmidt rearrangement of a secondary azide and a highly stereoselectively desymmetrizing intramolecular Schmidt reaction, respectively. To build the common spiro-γ-butyrolactone, a new protocol was carried out by utilizing an intramolecular ketone-ester condensation as the key transformation. The vicinal butyrolactone moiety of (±)-maistemonine was stereoselectively introduced via a one-pot procedure involving the epimerization at C-3 and carbonyl allylation/lactonization. Moreover, (±)-stemonamide was divergently synthesized from a common intermediate, and (±)-isomaistemonine was obtained via the epimerization of (±)-maistemonine at C-12

    Total Synthesis of (±)-Maistemonine, (±)-Stemonamide, and (±)-Isomaistemonine

    No full text
    A full account of the total synthesis of (±)-maistemonine, (±)-stemonamide, and (±)-isomaistemonine is presented. Two approaches have been developed to construct the basic pyrrolo­[1,2-a]­azepine core of the Stemona alkaloids, featuring a tandem semipinacol/Schmidt rearrangement of a secondary azide and a highly stereoselectively desymmetrizing intramolecular Schmidt reaction, respectively. To build the common spiro-γ-butyrolactone, a new protocol was carried out by utilizing an intramolecular ketone-ester condensation as the key transformation. The vicinal butyrolactone moiety of (±)-maistemonine was stereoselectively introduced via a one-pot procedure involving the epimerization at C-3 and carbonyl allylation/lactonization. Moreover, (±)-stemonamide was divergently synthesized from a common intermediate, and (±)-isomaistemonine was obtained via the epimerization of (±)-maistemonine at C-12

    Total Synthesis of (±)-Maistemonine, (±)-Stemonamide, and (±)-Isomaistemonine

    No full text
    A full account of the total synthesis of (±)-maistemonine, (±)-stemonamide, and (±)-isomaistemonine is presented. Two approaches have been developed to construct the basic pyrrolo­[1,2-a]­azepine core of the Stemona alkaloids, featuring a tandem semipinacol/Schmidt rearrangement of a secondary azide and a highly stereoselectively desymmetrizing intramolecular Schmidt reaction, respectively. To build the common spiro-γ-butyrolactone, a new protocol was carried out by utilizing an intramolecular ketone-ester condensation as the key transformation. The vicinal butyrolactone moiety of (±)-maistemonine was stereoselectively introduced via a one-pot procedure involving the epimerization at C-3 and carbonyl allylation/lactonization. Moreover, (±)-stemonamide was divergently synthesized from a common intermediate, and (±)-isomaistemonine was obtained via the epimerization of (±)-maistemonine at C-12

    Total Synthesis of (±)-Maistemonine, (±)-Stemonamide, and (±)-Isomaistemonine

    No full text
    A full account of the total synthesis of (±)-maistemonine, (±)-stemonamide, and (±)-isomaistemonine is presented. Two approaches have been developed to construct the basic pyrrolo­[1,2-a]­azepine core of the Stemona alkaloids, featuring a tandem semipinacol/Schmidt rearrangement of a secondary azide and a highly stereoselectively desymmetrizing intramolecular Schmidt reaction, respectively. To build the common spiro-γ-butyrolactone, a new protocol was carried out by utilizing an intramolecular ketone-ester condensation as the key transformation. The vicinal butyrolactone moiety of (±)-maistemonine was stereoselectively introduced via a one-pot procedure involving the epimerization at C-3 and carbonyl allylation/lactonization. Moreover, (±)-stemonamide was divergently synthesized from a common intermediate, and (±)-isomaistemonine was obtained via the epimerization of (±)-maistemonine at C-12

    Total Synthesis of (±)-Maistemonine, (±)-Stemonamide, and (±)-Isomaistemonine

    No full text
    A full account of the total synthesis of (±)-maistemonine, (±)-stemonamide, and (±)-isomaistemonine is presented. Two approaches have been developed to construct the basic pyrrolo­[1,2-a]­azepine core of the Stemona alkaloids, featuring a tandem semipinacol/Schmidt rearrangement of a secondary azide and a highly stereoselectively desymmetrizing intramolecular Schmidt reaction, respectively. To build the common spiro-γ-butyrolactone, a new protocol was carried out by utilizing an intramolecular ketone-ester condensation as the key transformation. The vicinal butyrolactone moiety of (±)-maistemonine was stereoselectively introduced via a one-pot procedure involving the epimerization at C-3 and carbonyl allylation/lactonization. Moreover, (±)-stemonamide was divergently synthesized from a common intermediate, and (±)-isomaistemonine was obtained via the epimerization of (±)-maistemonine at C-12

    Total Synthesis of (±)-Maistemonine, (±)-Stemonamide, and (±)-Isomaistemonine

    No full text
    A full account of the total synthesis of (±)-maistemonine, (±)-stemonamide, and (±)-isomaistemonine is presented. Two approaches have been developed to construct the basic pyrrolo­[1,2-a]­azepine core of the Stemona alkaloids, featuring a tandem semipinacol/Schmidt rearrangement of a secondary azide and a highly stereoselectively desymmetrizing intramolecular Schmidt reaction, respectively. To build the common spiro-γ-butyrolactone, a new protocol was carried out by utilizing an intramolecular ketone-ester condensation as the key transformation. The vicinal butyrolactone moiety of (±)-maistemonine was stereoselectively introduced via a one-pot procedure involving the epimerization at C-3 and carbonyl allylation/lactonization. Moreover, (±)-stemonamide was divergently synthesized from a common intermediate, and (±)-isomaistemonine was obtained via the epimerization of (±)-maistemonine at C-12

    Total Synthesis of (±)-Maistemonine, (±)-Stemonamide, and (±)-Isomaistemonine

    No full text
    A full account of the total synthesis of (±)-maistemonine, (±)-stemonamide, and (±)-isomaistemonine is presented. Two approaches have been developed to construct the basic pyrrolo­[1,2-a]­azepine core of the Stemona alkaloids, featuring a tandem semipinacol/Schmidt rearrangement of a secondary azide and a highly stereoselectively desymmetrizing intramolecular Schmidt reaction, respectively. To build the common spiro-γ-butyrolactone, a new protocol was carried out by utilizing an intramolecular ketone-ester condensation as the key transformation. The vicinal butyrolactone moiety of (±)-maistemonine was stereoselectively introduced via a one-pot procedure involving the epimerization at C-3 and carbonyl allylation/lactonization. Moreover, (±)-stemonamide was divergently synthesized from a common intermediate, and (±)-isomaistemonine was obtained via the epimerization of (±)-maistemonine at C-12
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