Two Efficient Cascade Reactions to Synthesize Substituted Furocoumarins
摘要:
We have developed two efficient one-pot reactions to generate furo[3,2-c]coumarins and chlorofuro[3,2-c]coumarins through addition/cyclization/oxidation and chlorination. One cascade addition/cyclization/oxidation sequence of 1 with H2O in the presence of 20% CuCl as Lewis acid under an air atmosphere generated the 2-substituted-4H-furo[3,2-c]chromen-4-one 2. Another sequence in the presence of 10% CuBr and excess CuCl2 as the oxidant afforded the 3-chloro2-substituted-4H-furo[3,2-c]chromen-4-one 3.
Synthesis of novel functional polycyclic chromones through Michael addition and double cyclizations
作者:Yang Liu、Liping Huang、Fuchun Xie、Xuxing Chen、Youhong Hu
DOI:10.1039/c0ob01000f
日期:——
2-halobenzylic nitriles (esters or amides) for the synthesis of novel functional polycyclic chromenones has been developed. This tandem process involves multiple reactions, such as Michael addition and double cyclizations without a transition metal catalyst.
A Base-Promoted Tandem Reaction of 3-(1-Alkynyl)chromones with 1,3-Dicarbonyl Compounds: An Efficient Approach to Functional Xanthones
作者:Lizhi Zhao、Fuchun Xie、Gang Cheng、Youhong Hu
DOI:10.1002/anie.200902618
日期:2009.8.17
No need for a transition‐metal catalyst is characteristic for the tandem process presented herein to obtain functionalizedxanthones. The sequence involves multiple reactions, such as Michael addition‐elimination/cyclization/1,2‐addition/elimination reactions (see scheme).
C-Alkynylation of Chromones by Sonogashira Reaction
作者:Tamás Patonay、István Pazurik、Anita Ábrahám
DOI:10.1071/ch13006
日期:——
Sonogashira reaction of bromochromones and -flavones with a bromine atom on their benzene or heterocyclic ring with various terminal alkynes gave the desired products with nearly the same efficiency as the previously used iodine derivatives. The coupling reactions were performed in the presence of [tetrakis(triphenylphosphine)palladium(0)], copper(i) co-catalyst, and triethylamine, resulting in the
A novel and efficient method for the construction of 4-(3-chromonyl)furo[3,2-c]-1-benzopyran scaffold by molecular iodine-induced cascadereaction between 3-(1-alkynyl)chromone and 1-(2-hydroxyphenyl)-3-N,N-dimethylaminoprop-2-ene-1-one is described. Two new C–O, one C–C, and one C–I bonds are formed in this one-pot cascadereaction. This tandem process involves Michael addition and double annulation
通过分子碘诱导的3-(1-炔基)色酮与1-(2)间的级联反应构建4-(3-色酰基)呋喃并[3,2 - c ] -1-苯并吡喃骨架的新颖有效的方法描述了(-羟基苯基)-3 - N,N-二甲基氨基丙-2-烯-1-酮。在这一一锅级联反应中形成了两个新的C–O,一个C–C和一个C–I键。此串联过程涉及在温和条件下进行迈克尔加成和双环化反应,无需使用过渡金属,惰性气氛或干燥溶剂。产品的脱碘也完成了。
A base-promoted desalicyloylative dimerization of 3-(1-alkynyl)chromones: An unusual approach to 2-alkynyl xanthones
作者:Fuchun Xie、Xuan Pan、Shijun Lin、Youhong Hu
DOI:10.1039/b925234g
日期:——
A novel base-promoted cascade desalicyloylative dimerization of 3-(1-alkynyl)chromones to produce 2-alkynyl xanthones has been developed. This tandem process involves multiple reactions, such as Michael additions/cyclizations/desalicyloylation without a transition metal catalyst and inert atmosphere.