5-Endo-dig iodocyclisations of alk-3-yn-1,2-diols 4, followed by in situ dehydration, lead to good yields of beta-iodofurans 5, which can subsequently be converted into a wide range of derivatives 6-13, using transition metal-catalysed coupling reactions or halogen-metal exchange.
Synthesis of Highly Substituted 3-Formylfurans by a Gold(I)-Catalyzed Oxidation/1,2-Alkynyl Migration/Cyclization Cascade
作者:Tao Wang、Shuai Shi、Max M. Hansmann、Eva Rettenmeier、Matthias Rudolph、A. Stephen K. Hashmi
DOI:10.1002/anie.201310146
日期:2014.4.1
3‐Formylfuran derivatives are core structures of a variety of bioactive natural products. However, procedures for their preparation are still rare and generally inefficient in terms of atom economy: These methods require multiple steps or harsh reaction conditions and show selectivity problems. An efficient gold(I)‐catalyzed cascade reaction that leads to 3‐formylfurans from easily accessible starting
By the design of suitable starting materials, a silver(I)‐catalyzed epoxide ring‐opening/1,2‐acylmigration/cyclization cascade has been developed, which allowed us to systematically prepare unsymmetrical 3‐formylfurans. Various 3‐formylfurans were prepared in good to excellent yields. In addition, the distinct fluorescence properties of 3‐formylfurans in solution and the solid state are disclosed
Pd/Cu-catalyzed cascade Sonogashira coupling/cyclization reactions to highly substituted 3-formyl furans
作者:Jingyu Yang、Chengyu Wang、Xin Xie、Hongfeng Li、Ende Li、Yanzhong Li
DOI:10.1039/c0ob00985g
日期:——
An efficient palladium/copper-catalyzed approach to the synthesis of highlysubstituted 3-formyl furans from the reactions of readily available α-bromoenaminones with terminal alkynes has been developed. This methodology was realized by the cascadereactions of Sonogashira coupling and the subsequent intramolecular cyclization.
Synthesis of Fully Substituted 3-Formyl-4-iodofurans<i>via</i>a Gold(I)-Catalyzed Oxidation/1,2-Alkynyl Migration/Cyclization/Iodination Cascade
作者:Tao Wang、Shuai Shi、Matthias Rudolph、A. Stephen K. Hashmi
DOI:10.1002/adsc.201400356
日期:2014.7.7
A highly efficient gold(I)‐catalyzed cascade reaction for the synthesis of fullysubstituted 3‐formyl‐4‐iodofurans has been developed. Mechanistic investigations indicate a reaction pathway that involves a direct iodination reaction of the organogold intermediate via functionalization of the AuC(sp2) bond, instead of a direct iodination of the 3‐formylfurans.