Cooperative Rh ₂ (OAc) ₄ /Chiral Phosphoric Acid‐Catalyzed (3 + 3)‐Cycloadditions of Pyrrole‐3‐Methides and Carbonyl Ylides

A stereoselective (3 + 3)‐cycloaddition between pyrrole‐3‐methides and carbonyl ylides, both generated in situ, has been developed to access densely substituted oxa‐bridged cyclohepta[1,2‐ b ]pyrroles in a single synthetic step. This transformation is enabled by a cooperative dual‐catalytic system comprising rhodium(II) acetate and a chiral phosphoric acid, each operating in separate catalytic cycles to generate the key transient intermediates. The reaction delivers structurally complex products bearing three stereogenic centers, two of which are quaternary. Excellent yields, high levels of enantioselectivity, and low to moderate diastereoselectivity are additional key features of this process. This methodology provides a straightforward synthetic access to valuable heterocyclic scaffolds with potential applications in synthetic and medicinal chemistry.