Kondoh Azusa, Aita Kohei, Terada Masahiro
Research and Analytical Center for Giant Molecules, Graduate School of Science, Tohoku University, Aramaki, Aoba-ku, Sendai, 980-8578, Japan.
Department of Chemistry, Graduate School of Science, Tohoku University, Aramaki, Aoba-ku, Sendai, 980-8578, Japan.
Chemistry. 2023 May 2;29(25):e202300132. doi: 10.1002/chem.202300132. Epub 2023 Mar 17.
Efficient methods for the synthesis of two types of furan-fused tricyclic compounds were developed based on a regiodivergent intramolecular carbometalation strategy using 2-(2'-alkynylaryl)-3-iodofurans as a common substrate. The iodine-magnesium exchange/copper-mediated 6-endo-anti intramolecular carbometalation sequence followed by nucleophilic substitution or palladium-catalyzed cross-coupling provided 2,3,4,5-tetrasubstituted naphtho[1,2-b]furans. On the other hand, the formal intramolecular 5-exo-anti carbopalladation/cross-coupling sequence afforded 2,3-disubstituted 4-alkylidene-4H-indeno[1,2-b]furans. The present methods provide new access to a wide range of well-organized polysubstituted naphtho[1,2-b]furans and indeno[1,2-b]furans in a positional selective manner that are otherwise difficult to access.
基于区域发散性分子内碳金属化策略，以2-(2'-炔基芳基)-3-碘代呋喃为通用底物，开发了两种合成呋喃稠合三环化合物的有效方法。碘-镁交换/铜介导的6-内型-反式分子内碳金属化序列，随后进行亲核取代或钯催化的交叉偶联反应，得到了2,3,4,5-四取代萘并[1,2-b]呋喃。另一方面，形式上的分子内5-外型-反式碳钯化/交叉偶联序列得到了2,3-二取代-4-亚烷基-4H-茚并[1,2-b]呋喃。本方法以位置选择性的方式为一系列结构规整的多取代萘并[1,2-b]呋喃和茚并[1,2-b]呋喃提供了新的合成途径，而这些化合物用其他方法很难合成。
