Asymmetric Alkenyl C−H Functionalization by CpxRhIII forms 2H‐Pyrrol‐2‐ones through 4+1‐Annulation of Acryl Amides and Allenes

-catalyzed enantioselective alkenyl C-H functionalization/4+1 annulation of acryl amides and allenes is reported. The described transformation provides straightforward access to enantioenriched α,β-unsaturated-γ-lactams bearing a quaternary stereocenter. The reaction operates under mild conditions, displays a broad functional-group tolerance, and provides 2H-pyrrol-2-ones with excellent selectivity of up to 97:3 er. Such scaffolds are frequently found in natural products and synthetic bioactive compounds and are of significant synthetic value. It is noteworthy that the allene serves as a one-carbon unit in the 4+1-annulation.