Cyclotrimerization of Enaminones: An Efficient Method for the Synthesis of 1,3,5-Triaroylbenzenes
作者:Ibrahim Elghamry
DOI:10.1055/s-2003-41056
日期:——
An efficient method for the synthesis of 1,3,5-triaroylbenzenes 2a-f by cyclotrimerization of enaminones 1a-f in acetic acid/pyridine (4:1) is illustrated. The structures of the products have been delineated by spectroscopic methods.
A New Organocatalytic Process of Cyclotrimerization of Acetylenic Ketones Mediated by 2,4-Pentanedione
作者:Song Xue、Qing-Fa Zhou、Fei Yang、Qing-Xiang Guo
DOI:10.1055/s-2007-967997
日期:2007.2
organocatalytic process of cyclotrimerization of the aliphatic and aromatic acetylenic ketones was developed. The reaction catalyzed by DMAP in the presence of 2,4-pentanedione gave 1,3,5-trisubstituted benzenes in almost quantitative yields under very mild conditions. 2,4-Pentanedione was used as a cocatalyst to promote the reaction efficiently, particularly for aliphatic acetylenic ketones.
The unusual transformation of β-aryl-β-haloacroleins into valuable triaroylbenzenes is reported by the first time. The convenient sequence takes advantage on the one step access to triaroylbenzenes. This work establishes that the presence of amine is required for the trimerization procedure since it is involved in the formation of iminium–enamine intermediate A.