Zhang Jie, Cheng Shijing, Cai Zhiqiang, Liu Ping, Sun Peipei
School of Chemistry and Materials Science, Jiangsu Provincial Key Laboratory of Material Cycle Processes and Pollution Control, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials , Nanjing Normal University , Nanjing 210023 , China.
J Org Chem. 2018 Aug 17;83(16):9344-9352. doi: 10.1021/acs.joc.8b01265. Epub 2018 Jul 13.
A mild and direct addition/cyclization cascade to construct methylsulfonylated and carbonylated benzofurans was accomplished using oxygen-linked 1,6-enynes as the starting materials. The interaction of NHI and DMSO promoted the generation of sulfur-containing radical and initiated the radical addition to the C═C double bond of 1,6-enyne cascade intramolecular 5- exo- dig cyclization. A wide range of oxygen-linked 1,6-enynes bearing various substituents were found to be suitable in this cascade process, providing benzofurans with dual functional groups in moderate to high yields. This method could also be utilized to synthesize benzothiophenes from sulfur-linked 1,6-enynes.
以氧连接的1,6-烯炔为起始原料，实现了一种温和直接的加成/环化串联反应，用于构建甲基磺酰化和羰基化的苯并呋喃。NHI与DMSO的相互作用促进了含硫自由基的生成，并引发自由基加成到1,6-烯炔的C═C双键上，进而发生分子内5-外向-双环化反应。发现多种带有不同取代基的氧连接的1,6-烯炔适用于该串联反应，能以中等到高的产率提供具有双官能团的苯并呋喃。该方法也可用于从硫连接的1,6-烯炔合成苯并噻吩。
