• Title/Summary/Keyword: ${\alpha}$-Keto amide/ester

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A New Synthesis of Triphenylphosphorane Ylide Precursors to α-Keto Amide/Ester and Tricarbonyl Units via Horner-Wadsworth-Emmons Reaction

  • Lee, Kie-Seung
    • Bulletin of the Korean Chemical Society
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    • v.31 no.10
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    • pp.2776-2782
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    • 2010
  • Newly developed Horner-Wadsworth-Emmons (HWE) reagents 5 having triphenylphosphorane ylide subunits readily condensed with various carbonyl compounds under mild reaction conditions to afford $\beta,\gamma$-unsaturated $\alpha$-keto triphenylphorane ylides in good to excellent yields, which were hydrogenated over Pd-C (10%)/$H_2$ (1 atm) to give the corresponding $\alpha$-keto triphenylphorane ylides in quasi-quantitative yields. These triphenyphosphorane ylides have been utilized as the precursors to $\alpha$-keto amide/ester and vicinal tricarbonyl units in Wasserman's synthetic protocols, and have previously been prepared only from carboxylic acids/acid chlorides. Our new approaches provide excellent alternatives for the synthesis of triphenylphosphorane ylide precursors to $\alpha$-keto amide/ester and vicinal tricarbonyl units directly from carbonyl compounds in good to excellent yields.

A Versatile Synthesis of α-Keto (cyanomethylene)triphenylphosphorane Ylides from Alkyl Halides Utilizing a Noble Phenylsulfonyl Reagent

  • Lee, Kieseung;Hwang, Chan-Yeon
    • Bulletin of the Korean Chemical Society
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    • v.34 no.10
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    • pp.2953-2958
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    • 2013
  • A noble phenylsulfonyl reagent 8 having ${\alpha}$-oxo (cyanomethylene)triphenylphosphorane ylide subunit readily condensed with various alkyl halides under basic conditions to afford ${\beta}$-alkyl-${\alpha}$-oxo-${\beta}$-phenylsulfonyl (cyanomethylene)triphenylphosphorane ylides 9 in excellent yields. These sulfonyl ylides 9 were then reductively desulfonylated with $Na(Hg)/Na_2HPO_4$ in the presence of methanol to provide ${\alpha}$-keto (cyanomethylene)-triphenylphosphorane ylides 2' in good to excellent yields. Our new synthetic approach offers an expeditious access to various ${\alpha}$-keto (cyanomethylene)triphenylphosphorane ylides from alkyl halides utilizing a new phenylsulfonyl reagent as the key reagent under mild reaction conditions in good overall yields.

An Efficient Synthesis of γ-Aminobutyric Acid-Derived Phospholipase A2 Inhibitors from Acyl Cyanophosphoranes and Amine Derivatives (아실 시아노포스포레인과 아민 유도체로 부터 γ-아미노부틸산에서 유도된 포스포리파제 A2 저해제의 효과적인 합성)

  • Lee, Kie-Seung;Kim, Dae-Keun
    • Journal of the Korean Chemical Society
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    • v.48 no.2
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    • pp.161-170
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    • 2004
  • A series of ${\gamma}$-aminobutyric acid-derived, potent human cytosolic phospholipase A$_2$ inhibitors have been prepared from acyl cyanophosphoranes and amine derivatives in a convergent manner. The ${\alpha}$-keto amide functionalities in the inhibitors have been introduced as electrophilic fragments via direct coupling reactions between the labile ${\alpha},{\beta}$-diketo nitriles and ${\gamma}$-aminobutyric acid t-butyl ester derivatives at -78 $^{\circ}C$ in moderate to good yields.