Pd‐Catalyzed Cascade Metallo‐Ene Cyclization/Metallo‐Carbene Coupling of Allenamides

A highly efficient palladium‐catalyzed cascade metallo‐ene/metallo‐carbene coupling reaction was developed to produce 2,3‐dihydropyrrole derivatives in high yields. In this transformation, two new Csp3−Csp2 and Csp2−Csp2 bonds were constructed in one‐pot. The alkene was one of the most easily functionalized groups, making it possible for these molecules to be transformed into more complex molecules. More importantly, the final product possessed an attractive 1,3,8‐trienes scaffold, which was difficult to be synthesized. A new type of cascade metallo‐ene cyclization/metallo‐carbene coupling of allenamides catalyzed by palladium is described. Allenamide substrates went through two π‐allyl palladium complex processes and migratory insertion of palladium carbene, and finally generates 2,3‐dihydropyrrole derivatives with a 1,3,8‐triene scaffold. Two new Csp3−Csp2 and Csp2−Csp2 bonds were constructed in one pot.