A Concise Assembly of Electron‐Deficient 2,4‐Dienes and 2,4‐Dienals: Regio‐ and Stereoselective exo ‐Diels–Alder and Redox Reactions through Sequential Amine and Carbene Catalysis

Ideal relay catalysis : A γ,δ‐regioselective anomalous exo ‐Diels–Alder reaction with electron‐deficient β‐substituted 2,4‐dienes and 2,4‐dienals has been developed by using trienamine activation. The resulting multifunctional cycloadducts contain perfectly positioned functional groups, thereby facilitating a 1,5‐hydride transfer from the C–H group of an aldehyde to an activated alkene under sequential catalysis of a carbene (see scheme).