Copper‐Catalyzed Enantioselective Inverse Electron‐Demand Hetero‐Diels–Alder Reactions of Diazadienes with Enol Ethers: Efficient Synthesis of Chiral Pyridazines

A highly efficient and enantioselective inverse electron‐demand hetero‐Diels–Alder reaction of in situ generated 1,2‐diaza‐1,3‐dienes with enol ethers has been developed with the use of a chiral copper/bisoxazoline complex as the catalyst. The reaction exhibits high enantioselectivity (up to 90% ee ) and provides a robust and powerful method to synthesize a variety of structurally diverse and densely substituted chiral pyridazine derivatives in good to excellent yields.