Metal-Free Tandem Friedel–Crafts/Lactonization Reaction to Benzofuranones Bearing a Quaternary Center at C3 Position
摘要:
A metal-free tandem Friedel-Crafts/lactonization reaction to 3,3-diaryl or 3-alkyl-3-aryl benzofuranones catalyzed by HClO4 was reported. A variety of tertiary alpha-hydroxy acid esters could readily react with substituted phenols to afford the desired products in rich diversity. The synthetic utility of the products was demonstrated by the synthesis of polycyclic compounds. H-1 NMR studies supported that this tandem reaction proceeded via tandem Friedel-Crafts/lactonization sequence.
A metal-free approach to highly functionalized 3-substituted-3-arylbenzofuran-2(3<i>H</i>)-ones
作者:Bhaskar B. Dhotare、Sahil Kumar、Amey Wadawale、Sandip K. Nayak、Mukesh Kumar、Dibakar Goswami
DOI:10.1039/d2nj03404b
日期:——
A novel metal-free approach to the synthesis of a variety of 3-substituted-3-arylbenzofuran-2(3H)-ones is developed via H2SO4-mediated dehydrative substitution of 3-hydroxy-3-phenylbenzofuran-2(3H)-ones with electron-rich arenes/1,3-diones/alcohols/thiols as nucleophiles in moderate to good yields. Mechanistically, the substitution with the alkoxy group proceeds via a phenolic–hydroxyester intermediate
通过H 2 SO 4介导的3-羟基-3-苯基苯并呋喃-2( 3 H )-具有富电子芳烃/1,3-二酮/醇/硫醇作为亲核试剂,产率适中。从机理上讲,烷氧基的取代通过酚-羟基酯中间体进行,并通过级联脱水-再内酯化步骤形成所需的产物。
Metal-Free Tandem Friedel–Crafts/Lactonization Reaction to Benzofuranones Bearing a Quaternary Center at C3 Position
作者:Long Chen、Feng Zhou、Tao-Da Shi、Jian Zhou
DOI:10.1021/jo300395x
日期:2012.5.4
A metal-free tandem Friedel-Crafts/lactonization reaction to 3,3-diaryl or 3-alkyl-3-aryl benzofuranones catalyzed by HClO4 was reported. A variety of tertiary alpha-hydroxy acid esters could readily react with substituted phenols to afford the desired products in rich diversity. The synthetic utility of the products was demonstrated by the synthesis of polycyclic compounds. H-1 NMR studies supported that this tandem reaction proceeded via tandem Friedel-Crafts/lactonization sequence.