Palladium-catalyzed diastereoselective synthesis of 2,2,3-trisubstituted dihydrobenzofurans via intramolecular trapping of O-ylides with activated alkenes
An efficient palladium catalyzed diastereoselective synthesis of 2,2,3-trisubstituted dihydrobenzofurans has been accomplished in good yield as a single diastereomer. The transformation involves in-situ generation of oxonium ylide from 2-hydroxyphenyl substituted enone and diazo compound followed by intramolecular trapping via Michael addition. Successful integration of the developed method with intramolecular
Reaction of ethyl acetoacetate and 2′-hydroxychalcones: Efficient route to 9-aryl-6<i>H</i>-benzo[c]chromen-6-ones
作者:I. B. Masesane、O. Mazimba
DOI:10.4314/bcse.v28i2.12
日期:——
The reaction of ethyl acetoacetate and 2′-hydroxychalcones under atmospheric air to furnish a series of functionalized 6H-benzo[c]chromen-6-ones in moderate yields is reported. The reaction proceeds through trans-esterification, intra-molecular Michael addition, Robinson annulation and oxidative aromatization.
One-Pot Synthesis of O-Heterocycles or Aryl Ketones Using an InCl<sub>3</sub>/Et<sub>3</sub>SiH System by Switching the Solvent
作者:Wenqiang Jia、Qiumu Xi、Tianqi Liu、Minjian Yang、Yonghui Chen、Dali Yin、Xiaojian Wang
DOI:10.1021/acs.joc.9b00140
日期:2019.5.3
An efficient one-pot synthesis of O-heterocycles or aryl ketones has been achieved using Et3SiH in the presence of InCl3 via a sequential ionic hydrogenation reaction by switching the solvent. This methodology can be used to construct C–O bonds and to prepare conjugate reduction products, including chromans, tetrahydrofurans, tetrahydropyrans, dihydroisobenzofurans, dihydrochalcones, and 1,4-diones
An efficient synthesis of flavans from salicylaldehyde and acetophenone derivatives
作者:Ofentse Mazimba、Ishmael B. Masesane、Runner R. Majinda
DOI:10.1016/j.tetlet.2011.09.147
日期:2011.12
An efficient total synthesis of flavans from the reactions of salicylaldehyde and acetophenonederivatives is reported. The synthesis involves preparation of chalcones through an aldol reaction followed by reduction of both the double bond and the ketone using NaBH4 and an acetic acid mediated cyclization. Methoxy groups on the aromatic rings did not affect significantly the yields of the procedure
Synthesis of Functionalized Chromene and Chroman Derivatives via Cesium Carbonate Promoted Formal [4 + 2] Annulation of 2′-Hydroxychalcones with Allenoates
作者:Hossein Rouh、Yangxue Liu、Nandakumar Katakam、Lilian Pham、Yi-Long Zhu、Guigen Li
DOI:10.1021/acs.joc.8b02627
日期:2018.12.21
A new strategy has been established for the synthesis of functionalized chromene and chroman derivatives via a Cs2CO3-catalyzed domino addition of 2′-hydroxychalcone derivatives with allenoates, which can serve as a general avenue for the construction of multireplaced chromene derivatives. Chemoselectivity of this synthesis was found to depend on substituents on substrates. Good to excellent yields
已经建立了通过Cs 2 CO 3催化的2'-羟基查耳酮衍生物与烯丙酸酯的多米诺加成来合成官能化的色烯和苯并二氢吡喃衍生物的新策略,其可以用作构建多取代的色烯衍生物的一般途径。发现该合成的化学选择性取决于底物上的取代基。在简单和温和的条件下,在室温下获得了良好的优良收率。