Synthesis of novel multi-functionalized pyrrolidines by [3 + 2] dipolar cycloaddition of azomethine ylides and vinyl ketones

Abstract

An efficient and easy synthetic route to substituted pyrrolidine derivatives has been established through [3 + 2] dipolar cycloaddition of vinyl ketones and azomethine ylides. The reactions proceed smoothly, under mild conditions, affording moderate to high isolated yields (up to 88%) of the products, within a short reaction time (15–45 min), providing a series of novel potentially bioactive compounds. Mechanistic considerations revealed that this cycloaddition exclusively proceeds following endo-pathway which enables access to the cis-derivatives. The products that contain acetyl group at C4 easily undergo isomerization, as it was confirmed by monitoring of the reaction kinetics and DFT calculations.