Synthesis of functionalized chromones via organocatalysis
摘要:
A facile and versatile organocatalytic approach to access 2-substituted and 2,3-disubstituted chromone derivatives under mild conditions was developed, which was effectively catalyzed by novel proline phenylsulphonylhydrazide or pyrrolidine. As a result, diversely functionalized chromones were obtained in up to 99% yield. In addition, further modification of the corresponding chromones afforded novel polycyclic chromones. (C) 2014 Elsevier Ltd. All rights reserved.
Triton-B Adsorbed on Flysh: An Efficient Support for the Base Catalysed Reactions under Microwave Irradiations
作者:VIJENDER GOEL
DOI:10.13005/ojc/280422
日期:2012.12.22
application of Triton-Badsorbed on flyash (a waste material of thermal plants ) has been reported for the variety of basecatalysedreactions such as synthesis of cinnamic acids by Deobner reaction, synthesis of 1-(2-hydroxyphenyl)-5-phenylpent-4-ene-1, 3-diones by Baker- Venkataraman reaction and synthesis of 3-carboxycoumarins by knoevenagel reaction. This material also acts as a support for the reaction
作者:Xiaoyi Li、Zihao Li、Rong Zhang、Zhen Zhou、Yonghui Zhang、Yi Xia、Weijun Yao、Zhen Wang
DOI:10.1021/acs.orglett.3c00705
日期:2023.4.21
organocatalyzed stereoselective domino reaction as a facile approach to multicyclic spirooxindolederivatives bearing two stereogenic quaternary carbon atoms is reported. The alkyl-substituted chiral thiourea catalyst was efficient for the reaction to tolerate a wide range of substrates, furnishing a new class of spirooxindolederivatives bearing an O,O-acetal-fused tricyclic skeleton or tetrahydroxanthone moiety
The Asymmetric Synthesis of Polycyclic Tetrahydroxanthone via the Cascade Reaction of Alkene‐Substituted 1,3‐diketones and Alkenyloxindoles
作者:Rong Zhang、Wenhui Wang、Yonghui Zhang、Yushuang Chen、Weijun Yao、Zhen Wang
DOI:10.1002/adsc.202400113
日期:2024.4.23
An enantioselective access to polycyclic tetrahydroxanthone compounds was achieved through an organocatalyzed cascade reaction of alkene‐substituted 1,3‐diketones and alkenyloxindoles, using quinine‐derivedsquaramide as an efficient catalyst. It afforded a variety of optically active spirooxindole‐based tetrahydroxanthones with 18‐94% yields, >19:1 dr, and 86‐99% ee.
Flavones were prepared using a one-pot procedure starting from the corresponding 2'-hydroxyacetophenones. The latter were treated with 3 equiv of aroyl chloride in wet K2CO3/acetone (1% w/w water) to afford a good yield of flavone and a smaller amount of 3-aroylflavone. Evidence was obtained that the reaction proceeds via a triketone intermediate. When the reactants were heated in 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and pyridine, the 3-aroylflavone was obtained exclusively. Use of a stoichiometric amount of aroyl chloride afforded only the corresponding flavone. (C) 2011 Elsevier Ltd. All rights reserved.
Gaggad, H. L.; Wadodkar, K. N.; Ghiya, B. J., Indian Journal of Chemistry - Section B Organic and Medicinal Chemistry, 1985, vol. 24, p. 1244 - 1247