A Formal [3 + 3] Cycloaddition Reaction. Improved Reactivity Using α,β-Unsaturated Iminium Salts and Evidence for Reversibility of 6π-Electron Electrocyclic Ring Closure of 1-Oxatrienes
摘要:
A detailed account regarding a formal [3 + 3] cycloaddition method using 4-hydroxy-2-pyrones and 1,3-diketones is described here. This formal cycloaddition reaction or annulation reaction is synthetically useful for constructing 2H-pyranyl heterocycles. The usage of alpha,beta-unsaturated iminium salts is significant in controlling competing reaction pathways to give exclusively 2H-pyrans. Most significantly, experimental evidence is provided to support the mechanism of this reaction that involves a sequential Knoevenagel condensation and a reversible 6pi-electron electrocyclic ringclosure of 1-oxatrienes.
DOI:
10.1021/jo020688t
作为产物:
描述:
Ethyl 5-(2,6-dimethoxyphenyl)-3,5-dioxopentanoate 150.0 ℃
、399.97 Pa
条件下,
以56%的产率得到6-(2,6-Dimethoxy-phenyl)-4-hydroxy-pyran-2-one
参考文献:
名称:
Synthesis and UV Studies of A Small Library of 6-Aryl-4-hydroxy-2-pyrones. A Relevant Structural Feature for the Inhibitory Property of Arisugacin Against Acetylcholinesterase
摘要:
4-Hydroxypyrones belong to an important class of compounds not only because of their medicinal significance, but also because they represent a common structural feature among natural products that ale biologically relevant. We describe here preparations of a small library of 6-aryl-4-hydroxy-pyrones which represent structural analogs of the DE-ring of arisugacin, a potent and selective inhibitor against acetylcholinesterase. Given the structural significance of the DE-ring in the inhibitory activity of arisugacin, chemical shifts of relevant protons on the pyrone ring are compared, and distinct features in UV absorptions of these 6-aryl-4-hydroxy-pyrones are described. (C) 1999 Elsevier Science Ltd. All rights reserved.
A Formal [3 + 3] Cycloaddition Reaction. Improved Reactivity Using α,β-Unsaturated Iminium Salts and Evidence for Reversibility of 6π-Electron Electrocyclic Ring Closure of 1-Oxatrienes
作者:Hong C. Shen、Jiashi Wang、Kevin P. Cole、Michael J. McLaughlin、Christopher D. Morgan、Christopher J. Douglas、Richard P. Hsung、Heather A. Coverdale、Aleksey I. Gerasyuto、Juliet M. Hahn、Jia Liu、Heather M. Sklenicka、Lin-Li Wei、Luke R. Zehnder、Craig A. Zificsak
DOI:10.1021/jo020688t
日期:2003.3.1
A detailed account regarding a formal [3 + 3] cycloaddition method using 4-hydroxy-2-pyrones and 1,3-diketones is described here. This formal cycloaddition reaction or annulation reaction is synthetically useful for constructing 2H-pyranyl heterocycles. The usage of alpha,beta-unsaturated iminium salts is significant in controlling competing reaction pathways to give exclusively 2H-pyrans. Most significantly, experimental evidence is provided to support the mechanism of this reaction that involves a sequential Knoevenagel condensation and a reversible 6pi-electron electrocyclic ringclosure of 1-oxatrienes.
Synthesis and UV Studies of A Small Library of 6-Aryl-4-hydroxy-2-pyrones. A Relevant Structural Feature for the Inhibitory Property of Arisugacin Against Acetylcholinesterase
作者:Christopher J. Douglas、Heather M. Sklenicka、Hong C. Shen、David S. Mathias、Shane J. Degen、Geoffrey M. Golding、Christopher D. Morgan、Regina A. Shih、Kristen L. Mueller、Lisa M. Scurer、Erik W. Johnson、Richard P. Hsung
DOI:10.1016/s0040-4020(99)00847-9
日期:1999.11
4-Hydroxypyrones belong to an important class of compounds not only because of their medicinal significance, but also because they represent a common structural feature among natural products that ale biologically relevant. We describe here preparations of a small library of 6-aryl-4-hydroxy-pyrones which represent structural analogs of the DE-ring of arisugacin, a potent and selective inhibitor against acetylcholinesterase. Given the structural significance of the DE-ring in the inhibitory activity of arisugacin, chemical shifts of relevant protons on the pyrone ring are compared, and distinct features in UV absorptions of these 6-aryl-4-hydroxy-pyrones are described. (C) 1999 Elsevier Science Ltd. All rights reserved.