Synthesis of C2 Substituted Benzothiophenes via an Interrupted Pummerer/[3,3]-Sigmatropic/1,2-Migration Cascade of Benzothiophene <i>S</i>
-Oxides
作者:Zhen He、Harry J. Shrives、José A. Fernández-Salas、Alberto Abengózar、Jessica Neufeld、Kevin Yang、Alexander P. Pulis、David J. Procter
DOI:10.1002/anie.201801982
日期:2018.5.14
Functionalized benzothiophenes are important scaffolds found in molecules with wide ranging biological activity and in organic materials. We describe an efficient, metal‐free synthesis of C2 arylated, allylated, and propargylated benzothiophenes. The reaction utilizes synthetically unexplored yet readily accessible benzothiophene S‐oxides and phenols, allyl‐, or propargyl silanes in a unique cascade
功能化的苯并噻吩是在具有广泛生物活性的分子和有机材料中发现的重要支架。我们描述了一种高效,无金属的C2芳基化,烯丙基化和炔丙基化苯并噻吩的合成方法。该反应以独特的级联顺序利用合成的未探索但易于获得的苯并噻吩S-氧化物和苯酚,烯丙基或炔丙基硅烷。苯并噻吩S-氧化物与偶合剂之间的Pummerer反应中断,生成的aromatic盐缺乏芳香性,因此容易实现[3,3]-σ重排。随后生成的苯并噻吩盐经历了以前未经探索的1,2-迁移,以进入C2功能化的苯并噻吩。