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.
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.
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.