Gold‐Catalyzed One‐Pot A 3 ‐Coupling/1,5‐Hydride Shift/Schmittel‐Type Cyclization: From Aldehydes, Amines and Alkynes to the Synthesis of Benzo[ b ]fluorenes

A step‐economic gold‐catalyzed one‐pot synthesis of benzo[ b ]fluorenes, from aldehydes, alkynes and amines, proceeding via an A 3 ‐coupling/1,5‐hydride shift/Schmittel‐type cyclization is described. The formation of the allene intermediate is not dependent on a previous installation of reaction triggers, and upon cyclization delivered benzo[ b ]fluorenes. With this method, just by an easy modification of the starting materials in a modular way, nineteen benzo[ b ]fluorenes, bearing different substituents Ar 1 , Ar 2 and Ar 3 , were prepared. Overall, three new carbon–carbon bonds are formed in one‐pot.