A novel catalytic reaction has been developed for the nucleophilic addition of terminal alkynes toα,β‐unsaturated‐γ‐lactams via a cyclic N‐acyliminium ion intermediate. This simple reaction pro‐ceeds rapidly under mild conditions, and provided a practical approach for the synthesis of a wide range of 5‐alkynyl‐2‐pyrrolidinones in moderate to good yields （45%–76%）.
