Double annulations of dihydroxy- and diacetoxy-dialkynylbenzenes. An efficient construction of benzodifurans
作者:Zhiqiang Liang、Shengming Ma、Jihong Yu、Ruren Xu
DOI:10.1016/j.tet.2007.10.051
日期:2007.12
An efficient synthetic route to construct disubstituted benzodifurans from dihydroxy- or diacetoxy-dialkynylbenzenes utilizing Cs2CO3 or Pd(OAc)2/Cs2CO3 promoted double annulations is described. The scope for the reaction in the presence of a catalytic amount of Pd(OAc)2 is more general. In addition, it was observed that NaOH-promoted reaction of diacetoxy-dialkynylbenzenes may directly afford in THF/MeOH/H2O
描述了一种利用Cs 2 CO 3或Pd(OAc)2 / Cs 2 CO 3促进的双环法从二羟基-或二乙酰氧基-二炔基苯构建二取代的苯并呋喃的有效合成途径。在催化量的Pd(OAc)2存在下反应的范围更一般。此外,已观察到,NaOH促进的二乙酰氧基-二炔基苯的反应可以在80°C的苯并二呋喃中以单锅法通过水解和双环化直接在THF / MeOH / H 2 O中提供。但是,在大多数情况下,反应的选择性较低,提供了双环化产物和单环化-水解产物的混合物。
Palladium-Catalyzed Double Annulations To Construct Multisubstituted Benzodifurans
作者:Zhiqiang Liang、Shengming Ma、Jihong Yu、Ruren Xu
DOI:10.1021/jo7016263
日期:2007.11.1
Efficient synthetic routes to construct multisubstituted benzo[1,2-b:5,4-b‘]difurans and benzo[1,2-b:4,5-b‘]difurans from bis(allyloxy)bis(alkynyl)benzenes or bis(alkynyl)dihydroxybenzenes and allylic halides utilizing palladium-catalyzed double annulations is reported. By further applying a double ring-closing metathesis reaction, pentacyclic compounds were also prepared.
有效的合成路线来构建多取代苯并[1,2- b:5,4- b “] difurans和苯并[1,2- b:4,5- b ”]由二difurans(烯丙氧基)双(炔基)苯或据报道,利用钯催化的双环双(炔基)二羟基苯和烯丙基卤化物。通过进一步进行双闭环复分解反应,还制备了五环化合物。
Modular synthesis and photophysical and electrochemical properties of 2,3,5,6-tetraaryl-substituted benzo[1,2-b:5,4-b′]difurans
We developed a versatile synthesis of tetraaryl-substitutedbenzo[1,2-b:5,4-b′]difurans (m-BDFs) via a zinc-mediated intramolecular double cyclization reaction of 4,6-bis(phenylethynyl)-1,3-benzenediol, followed by a palladium-catalyzed cross-coupling reaction. In comparison with the corresponding benzo[1,2-b:4,5-b′]difuran (p-BDF) isomers reported previously, the m-BDFs are slightly wider between