Phosphine-Catalyzed Synthesis of 6-Substituted 2-Pyrones: Manifestation of <i>E</i>/<i>Z</i>-Isomerism in the Zwitterionic Intermediate
作者:Xue-Feng Zhu、Arnaud-Pierre Schaffner、Ronald C. Li、Ohyun Kwon
DOI:10.1021/ol050946j
日期:2005.7.1
We report a one-step phosphine-catalyzed annulation between aldehydes and ethyl allenoate to form 6-substituted 2-pyrones. The mechanistic rationale for this reaction requires explicit discussion of the EIZ-isomerism of the zwitterionic intermediate formed by the addition of a phosphine to the allenoate. Sterically demanding trialkylphosphines facilitate the shift of equilibrium toward the E-isomeric zwitterion and lead to the formation of 6-substituted 2-pyrones. Various aromatic as well as aliphatic aldehydes undergo the transformation in moderate to excellent yield.
Julia; Bullot, Bulletin de la Societe Chimique de France, 1959, p. 1689
作者:Julia、Bullot
DOI:——
日期:——
SOKOLOVSKAYA, S. V.;MOLDOVANOVA, L. K., XIMIYA GETEROTSIKL. SOEDIN., 1984, N 5, 616-618
作者:SOKOLOVSKAYA, S. V.、MOLDOVANOVA, L. K.
DOI:——
日期:——
Iodination of 6-aryl-2-pyrones
作者:S. V. Sokolovskaya、L. K. Moldovanova
DOI:10.1007/bf00514298
日期:1984.5
SOKOLOVSKAYA S. V.; MOLDOVANOVA L. K., XIMIYA GETEROTSIKL. SOEDIN., 1979, HO 2, 173-176