AgNO 3 ‐Catalysed Intramolecular Cyclization: Access to Functionalized Cyclopentanones and Spiro‐Cyclopentanones

An efficient AgNO 3 ‐catalysed method has been developed for the synthesis of functionalized cyclopentanones and spiro‐cyclopentanones through intramolecular cyclization between ynones and cyanoacrylate/aryl/alkylidene malononitrile using DBU as a base. Easy availability of starting materials and mild reaction conditions makes this protocol more feasible over previously reported methods. The functionalized cyclopentanones and spiro‐cyclopentanones were synthesized in good to excellent yields with a broad substrate scope.