A convenient and straightforward approach for the radical cascade cyclization/hydrolysis of CN‐containing 1,6‐enynes with simple ethers under metal‐ and base‐free conditions is described. This strategy provides a variety of valuable ethers‐substituted polyheterocycles via the construction of three C−C bonds, one C=O bond, and two new six‐membered rings within a single procedure. The resulting products can smoothly undergo follow‐up conversions to various useful scaffolds. The methodology shows excellent functional group tolerance, high step‐ and atom‐ economy, and mild reaction conditions, which can be further scaled up to gram quantity in a satisfactory yield.

A novel method for the ring‐opening/cyclization of cyclobutanone oxime esters with three different types of alkenes for the synthesis of valuable 2‐pyrrolidones and benzimidazo[2,1‐a]isoquinolin‐6(5H)‐ones is demonstrated for the first time, which uses CuCl as a catalyst and K2S2O8 as an oxidant in a biomass‐derived solvent 2‐methyltetrahydrofuran (2‐MeTHF). This protocol is highly efficient and gives full conversions of the substrates with good functional group compatibility. The use of economic and stable copper catalyst along with inorganic oxidant for the ring‐opening/cyclization in green solvent makes it a benign and sustainable strategy.