Regioselective Synthesis of Naphtho‐fused Heterocycles via Palladium(0)‐Catalyzed Tandem Reaction of N‐Tosylhydrazones

Abstract We have developed a palladium(0)‐catalyzed tandem process which involves the cross‐coupling reaction of N ‐tosylhydrazones with dibromide compounds followed by a sequence of intramolecular 5‐ exo ‐trig, 3‐ exo ‐trig cyclization, ring opening, and β‐hydride elimination to produce 6‐ endo ‐trig cyclized products. The strategy was successfully applied for the regioselective synthesis of substituted benzo[ b ]naphtho[2,1‐ d ]thiophenes, naphtho[1,2‐ b ]benzofurans, and benzo[ a ]carbazoles in moderate to excellent yields. magnified image