Iridium‐Catalyzed [4+2] Annulations of β‐Keto Sulfoxonium Ylides and o‐Phenylenediamines: Mild and Facile Synthesis of Quinoxaline Derivatives

A synthetic method for quinoxaline derivatives from the [4+2] annulation of β‐keto sulfoxonium ylides and o ‐phenylenediamine by using (Cp*IrCl 2 ) 2 catalyst is described. This novel protocol features mild reaction conditions, moderate to excellent yields, wide substrate scope, and high functional‐group compatibility. Moreover, this cyclization strategy was successfully applied in late‐stage modification for structurally complex bioactive compounds.