Synthesis of benzothienofuranones and dihydrobenzothienopyranones by palladium iodide-catalyzed carbonylative double cyclization
作者:Ida Ziccarelli、Raffaella Mancuso、Domenico Santandrea、Angela Altomare、Diego Olivieri、Carla Carfagna、Bartolo Gabriele
DOI:10.1016/j.jcat.2023.115101
日期:2023.11
second cyclization (possibly, through the formation of a palladacycle intermediate followed by reductive elimination), and Pd(0) reoxidation by oxygen (from air) used as external benign oxidant. Under similar conditions, 4-(2-(methylthio)phenyl)but-3-yn-1-ols, bearing a butynol moiety ortho to the methylthio group, led to a mixture of double cyclization and dicarbonylation products, however, by slightly
3-(2-(甲硫基)苯基)丙-2-炔-1-醇已通过 PdI 在一个合成步骤中成功转化为苯并[4,5]噻吩并[2,3-c]呋喃-1-酮2 /KI 催化的氧化羰基化双环化过程,在相对温和的条件下(1–10 mol% PdI 2、7 当量的 KI、80 °C、60 atm 的 4:1 CO-空气混合物)在 MeCN 中进行。该过程通过一系列有序步骤进行,涉及 5- endo - dig S-环化,碘化物促进随后锍盐的去甲基化,CO插入,第二次环化(可能通过形成环环中间体,然后还原消除),以及用作外部氧气(来自空气)的Pd(0)再氧化良性氧化剂。在类似的条件下,4-(2-(甲硫基)苯基)丁-3-yn-1-醇,带有与甲硫基邻位的丁炔醇部分,导致双环化和二羰基化产物的混合物,然而,通过稍微调整在该反应条件下,可以选择性地获得二氢苯并[4,5]噻吩并[3,2-c]吡喃-1-酮,且不形成二羰基化副产物。四