Indium(III)-Catalyzed Synthesis of Benzo[<i>b</i>]furans by Intramolecular Hydroalkoxylation of <i>ortho</i>-Alkynylphenols: Scope and Mechanistic Insights
作者:Lorena Alonso-Marañón、M. Montserrat Martínez、Luis A. Sarandeses、Enrique Gómez-Bengoa、José Pérez Sestelo
DOI:10.1021/acs.joc.8b00829
日期:2018.8.3
Indium(III) halides catalyze the hydroalkoxylation reaction of ortho-alkynylphenols to afford benzo[b]furans in good yields. The reaction proceeds with 5-endo-dig regioselectivity with a variety of phenols functionalized at the arene and alkyne moieties in high yields using InI3 (5 mol %) in DCE. Experimental and computational studies support a mechanism based on the indium(III) π-Lewis acid activation
卤化铟(III)催化邻炔基苯酚的加氢烷氧基化反应,以高收率提供苯并[ b ]呋喃。反应的进行与5-内切-挖区域选择性与各种在芳烃官能酚类和以高产率使用的InI炔基部分3在DCE(5摩尔%)。实验和计算研究支持了基于炔烃的铟(III)π-路易斯酸活化,然后进行苯酚的亲核加成和最终的原金属脱金属,得到相应的苯并[ b ]呋喃的机理。DFT计算表明二聚体In 2 I 6 是通过与炔烃和羟基的新型双配位而催化的物质。
A one-pot domino C–H, C–C activation in coumarins: a fast track to 2,3-diaryl benzo[<i>b</i>]furans
A new method for the arylative cyclization of o-alkynylphenols with aryldiazonium salts via dual photoredox/gold catalysis is described. The reaction proceeds smoothly at roomtemperature in the absence of base and/or additives and offers an efficient approach to benzofuran derivatives. The scope of the transformation is wide, and the limitations are discussed. The reaction is proposed to proceed through
One-Pot Synthesis of 2,3-Diarylbenzofurans via Sequential Iodocyclization and Pd-Catalyzed Suzuki Coupling Reactions of 2-Alkynylanisoles with Boronic Acids in Water
Abstract An efficient approach for the one-pot synthesis of 2,3-diarylbenzofurans via sequential iodocyclization and Pd-catalyzed Suzuki couplingreaction of 2-alkynylanisoles with boronic acids in water is reported. The protocol utilizes water as the solvent and there is no need to isolate the intermediate 3-iodine-2-arylbenzofurans, which exemplifies the ideal of green chemistry. Various 2-alkynylanisoles
skeleton efficiently. The application of this catalyst made it possible to carry out the reaction under phosphine-free and, in the case of the Sonogashira coupling, under copper-free conditions. The catalyst retained its activity in at least 7 subsequent runs in both types of reactions. Palladium leaching of less than 1% of the original amount used in the catalytic reaction was observed under optimized