I₂–DMSO‐Mediated Multicomponent [2+1+1+1] Annulation Reaction via Ethyl Nitroacetate C—NO₂ Bond Cleavage as a C1 Synthon: A Route to Multisubstituted β‐Pyrrolidinones Derivatives with a Quaternary Center

Comprehensive Summary A [2 + 1 + 1 + 1] cyclization reaction has been developed for the synthesis of multisubstituted β ‐pyrrolidinones from commercially available aryl methyl ketones, primary amines, and ethyl nitroacetate. In this I 2 –DMSO‐meditated process, the C—NO 2 bond of ethyl nitroacetate is cleaved, affording a C1 synthon, and the formation of two C—C and two C—N bonds and a quaternary carbon center are constructed in one pot. This method has good substrate compatibility and permits the late‐stage modification of pharmaceutical compounds.