16 research outputs found

    Asymmetric Synthesis of Substituted Homotropinones from <i>N</i>-Sulfinyl β-Amino Ketone Ketals. (−)-Euphococcinine and (−)-Adaline

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    Sulfinimine-derived N-sulfinyl β-amino ketone ketals on heating with NH4OAc:HOAc undergo a four-step intramolecular Mannich cyclization cascade reaction to give homotropinones, such as (−)-euphococcinine, in excellent yields as single isomers

    Asymmetric Synthesis of Substituted Homotropinones from <i>N</i>-Sulfinyl β-Amino Ketone Ketals. (−)-Euphococcinine and (−)-Adaline

    No full text
    Sulfinimine-derived N-sulfinyl β-amino ketone ketals on heating with NH4OAc:HOAc undergo a four-step intramolecular Mannich cyclization cascade reaction to give homotropinones, such as (−)-euphococcinine, in excellent yields as single isomers

    Asymmetric Synthesis of Substituted Homotropinones from <i>N</i>-Sulfinyl β-Amino Ketone Ketals. (−)-Euphococcinine and (−)-Adaline

    No full text
    Sulfinimine-derived N-sulfinyl β-amino ketone ketals on heating with NH4OAc:HOAc undergo a four-step intramolecular Mannich cyclization cascade reaction to give homotropinones, such as (−)-euphococcinine, in excellent yields as single isomers

    Asymmetric Total Synthesis of (<i>S</i>)-(+)-Cocaine and the First Synthesis of Cocaine C-1 Analogs from <i>N</i>-Sulfinyl β-Amino Ester Ketals

    No full text
    Sulfinimine-derived α,β-unsaturated pyrrolidine nitrones, on heating with Al(O-t-Bu)3, undergo a highly stereoselective intramolecular [3 + 2] cycloaddition to give tricyclic isoxazolidines, which are transformed in three-steps to give C-1 substituted cocaine analogs

    Asymmetric Total Synthesis of (<i>S</i>)-(+)-Cocaine and the First Synthesis of Cocaine C-1 Analogs from <i>N</i>-Sulfinyl β-Amino Ester Ketals

    No full text
    Sulfinimine-derived α,β-unsaturated pyrrolidine nitrones, on heating with Al(O-t-Bu)3, undergo a highly stereoselective intramolecular [3 + 2] cycloaddition to give tricyclic isoxazolidines, which are transformed in three-steps to give C-1 substituted cocaine analogs

    Asymmetric Total Synthesis of (<i>S</i>)-(+)-Cocaine and the First Synthesis of Cocaine C-1 Analogs from <i>N</i>-Sulfinyl β-Amino Ester Ketals

    No full text
    Sulfinimine-derived α,β-unsaturated pyrrolidine nitrones, on heating with Al(O-t-Bu)3, undergo a highly stereoselective intramolecular [3 + 2] cycloaddition to give tricyclic isoxazolidines, which are transformed in three-steps to give C-1 substituted cocaine analogs

    Asymmetric Total Synthesis of (<i>S</i>)-(+)-Cocaine and the First Synthesis of Cocaine C-1 Analogs from <i>N</i>-Sulfinyl β-Amino Ester Ketals

    No full text
    Sulfinimine-derived α,β-unsaturated pyrrolidine nitrones, on heating with Al(O-t-Bu)3, undergo a highly stereoselective intramolecular [3 + 2] cycloaddition to give tricyclic isoxazolidines, which are transformed in three-steps to give C-1 substituted cocaine analogs

    5(6)-<i>anti</i>-Substituted-2-azabicyclo[2.1.1]hexanes: A Nucleophilic Displacement Route

    No full text
    Nucleophilic displacements of 5(6)-anti-bromo substituents in 2-azabicyclo[2.1.1]hexanes (methanopyrrolidines) have been accomplished. These displacements have produced 5-anti-X-6-anti-Y-difunctionalized-2-azabicyclo[2.1.1]hexanes containing bromo, fluoro, acetoxy, hydroxy, azido, imidazole, thiophenyl, and iodo substituents. Such displacements of anti-bromide ions require an amine nitrogen and are a function of the solvent and the choice of metal salt. Reaction rates were faster and product yields were higher in DMSO when compared to DMF and with CsOAc compared to NaOAc. Sodium or lithium salts gave products, except with NaF, where silver fluoride in nitromethane was best for substitution by fluoride. The presence of electron-withdrawing F, OAc, N3, Br, or SPh substituents in the 6-anti-position slows bromide displacements at the 5-anti-position

    5(6)-<i>anti</i>-Substituted-2-azabicyclo[2.1.1]hexanes: A Nucleophilic Displacement Route

    No full text
    Nucleophilic displacements of 5(6)-anti-bromo substituents in 2-azabicyclo[2.1.1]hexanes (methanopyrrolidines) have been accomplished. These displacements have produced 5-anti-X-6-anti-Y-difunctionalized-2-azabicyclo[2.1.1]hexanes containing bromo, fluoro, acetoxy, hydroxy, azido, imidazole, thiophenyl, and iodo substituents. Such displacements of anti-bromide ions require an amine nitrogen and are a function of the solvent and the choice of metal salt. Reaction rates were faster and product yields were higher in DMSO when compared to DMF and with CsOAc compared to NaOAc. Sodium or lithium salts gave products, except with NaF, where silver fluoride in nitromethane was best for substitution by fluoride. The presence of electron-withdrawing F, OAc, N3, Br, or SPh substituents in the 6-anti-position slows bromide displacements at the 5-anti-position

    5(6)-<i>anti</i>-Substituted-2-azabicyclo[2.1.1]hexanes: A Nucleophilic Displacement Route

    No full text
    Nucleophilic displacements of 5(6)-anti-bromo substituents in 2-azabicyclo[2.1.1]hexanes (methanopyrrolidines) have been accomplished. These displacements have produced 5-anti-X-6-anti-Y-difunctionalized-2-azabicyclo[2.1.1]hexanes containing bromo, fluoro, acetoxy, hydroxy, azido, imidazole, thiophenyl, and iodo substituents. Such displacements of anti-bromide ions require an amine nitrogen and are a function of the solvent and the choice of metal salt. Reaction rates were faster and product yields were higher in DMSO when compared to DMF and with CsOAc compared to NaOAc. Sodium or lithium salts gave products, except with NaF, where silver fluoride in nitromethane was best for substitution by fluoride. The presence of electron-withdrawing F, OAc, N3, Br, or SPh substituents in the 6-anti-position slows bromide displacements at the 5-anti-position
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