Palladium-catalyzed annulative allylic alkylation for regioselective construction of indole-fused medium-sized cyclic ethers

A new palladium-catalyzed annulative allylic alkylation (AAA) reaction of 2-(indol-2-yl)phenols with dual allylic electrophiles such as isobutylene dicarbonate and butene dicarbonate is described, leading to the regioselective synthesis of tetracyclic medium-sized cyclic ethers possessing a bridged aryl-indole scaffold, namely, benzo[2,3]oxocino[4,5- b ]indoles and benzo[2,3]oxepino[4,5- b ]indoles, in good to excellent yields. This protocol demonstrates a broad substrate scope, good compatibility with substituents and high regioselectivity, providing a catalytic and flexible method for creating bridged aryl-indole skeletons.& COPY; 2023 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.