Stereoselective synthesis of enynones via base-catalyzed isomerization of 1,5-disubstituted-2,4-pentadiynyl silyl ethers or their alcohol derivatives
作者:Jingjin Chen、Guoqin Fan、Yuanhong Liu
DOI:10.1039/c0ob00344a
日期:——
1,5-Disubstituted-2,4-pentadiynyl silylethers undergo smooth desilylative isomerization to afford cis-enynones as major products with moderate stereoselectivities in the presence of a catalytic amount of KOtBu or DBU. While the isomerization reactions of their alcohol derivatives catalyzed by KOH, KOtBu or NaH take place efficiently to produce trans-enynones with high stereoselectivities. These reactions
1,5-二取代的2,4-戊二炔基甲硅烷基醚经过顺式脱甲硅烷基化异构化反应,以顺式-乙炔酮为主要产物,并在催化量的二甲基甲酰胺存在下,具有中等的立体选择性。KO Ť卜 或者 DBU。而其醇衍生物的异构化反应是通过酸值, KO Ť卜 或者 碳酸氢钠有效地产生具有高立体选择性的反式-乙炔酮。这些反应为合成具有广泛取代基的烯酮提供了方便实用的途径。
Gold-Catalyzed Cyclization of Alkynylaziridines as an Efficient Approach toward Functionalized <i>N</i>-Phth Pyrroles
作者:Xiangwei Du、Xin Xie、Yuanhong Liu
DOI:10.1021/jo902357x
日期:2010.1.15
An efficient access to N-phth pyrrroles via gold-catalyzed cycloisomerization of N-phth alkynylaziridines has been described. Functionalized pyrroles including pyrrole-2-carboxylates or 2-pyrrolyl ketone are easily constructed in generally good yields by this method. The resulting pyrroles can be further converted to N-amino pyrrole or 2-acyl pyrrole, which are important synthetic intermediates for
New Synthetic Approach for the Construction of Multisubstituted 2-Acyl Furans by the IBX-Mediated Cascade Oxidation/Cyclization of<i>cis</i>-2-En-4-yn-1-ols (IBX=2-Iodoxybenzoic Acid)