A Formal [3+2] Annulation of β‐Oxoamides and 3‐Alkyl‐ or 3‐Aryl‐Substituted Prop‐2‐Ynyl Sulfonium Salts: Substrate‐Controlled Chemoselective Synthesis of Substituted γ‐Lactams and Furans

A substrate‐controlled synthesis of substituted γ‐lactams and furans has been developed via a formal [3+2] annulation of β‐oxoamides and 3‐alkyl/arylprop‐2‐ynyl sulfonium salts in the presence of cesium carbonate in a chemoselective manner. This novel protocol features easily available starting materials, mild reaction conditions, simple execution, and good to excellent yields of products.