Silver(I)- or Copper(II)-Mediated Dearomatization of Aromatic Ynones: Direct Access to Spirocyclic Scaffolds

A high‐yielding silver(I)‐ or copper(II)‐catalyzed dearomatizing spirocyclization strategy allows the conversion of simple aromatic compounds that contain ynone substituents, including indole, anisole, pyrrole, and benzofuran derivatives, into functionalized spirocyclic scaffolds. A high‐yielding asymmetric variant furnishes spirocyclic indolenines in up to 89:11 e.r. Dearomatization: Simple achiral aromatic compounds that contain ynone substituents, including indole, anisole, pyrrole, and benzofuran derivatives, can be converted into complex chiral spirocyclic scaffolds. The silver(I)‐catalyzed dearomatizing spirocyclization typically provides the products in more than 95 % yield and up to 89:11 e.r.