Kitano Junya, Nishii Yuji, Miura Masahiro
Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita, Osaka565-0871, Japan.
Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives (ICS-OTRI), Osaka University, Suita, Osaka565-0871, Japan.
Org Lett. 2022 Aug 12;24(31):5679-5683. doi: 10.1021/acs.orglett.2c02030. Epub 2022 Jul 28.
Benzofuran is a privileged structure in many bioactive compounds; however, the controlled synthesis of C2,C3-nonsubstituted benzofurans has been scarce. In particular, cumbersome multistep processes are inevitable for the most inaccessible C4-substituted isomers. Herein, we report a Rh-catalyzed direct vinylene annulation of readily available -salicylic acid derivatives with vinylene carbonate to achieve selective construction of C4-substituted benzofurans. The Weinreb amide directing group facilitated the following product derivatization. The reaction mechanism was investigated by DFT calculations.
苯并呋喃是许多生物活性化合物中的一种优势结构；然而，C2、C3未取代的苯并呋喃的可控合成却很少见。特别是，对于最难获得的C4取代异构体，繁琐的多步过程是不可避免的。在此，我们报道了一种铑催化的、将容易获得的邻羟基苯甲酸衍生物与碳酸亚乙烯酯直接进行亚乙烯基环化反应，以实现C4取代苯并呋喃的选择性构建。Weinreb酰胺导向基团促进了后续的产物衍生化。通过密度泛函理论（DFT）计算对反应机理进行了研究。
