One-pot relay of Staudinger–aza-Wittig and Pd-catalyzed [3 + 2] cycloaddition: modular pyrrolidinone synthesis via in situ generated isocyanates from CO2

Abstract

We report an operationally simple, one-pot relay strategy that combines the Staudinger–aza-Wittig reaction with a Pd-catalyzed [3 + 2] cycloaddition for the modular synthesis of pyrrolidinones from readily available azides, activated vinylcyclo-propanes, and CO₂ as a sustainable C1 source, all under phosgene-free conditions. The method features a broad substrate scope and enables the efficient synthesis of ¹³C-labeled pyrrolidinones with nearly complete isotope incorporation. Moreover, it can be extended to carbon disulfide as an alternative C1 source.