Electromagnetic Mill-Promoted Palladium-Catalyzed Heck-Type Cyclization/Decarboxylative Coupling of (Z)-1-Iodo-1,6-diene with Propiolic Acids

Electromagnetic mill (EMM)-promoted solid-state cascade Heck-type cyclization/decarboxylative coupling of propiolic acid with (Z)-1-iodo-1,6-diene derivate was demonstrated. The reaction was realized via palladium catalysis, which is solvent-free and involves no additional heating. The collision between ferromagnetic rods could not only be a favor to the mixing between the solid substrates and the catalyst system, but also the thermogenic action could accelerate this transformation. More importantly, this EMM strategy realized multiple bond construction under mechanochemical conditions in one pot.

Palladium-Catalyzed Heck/Suzuki Tandem Reaction of (Z)-1-Iodo-1,6-dienes and Organoboronic Acids

The Heck/Suzuki tandem reaction has emerged as an essential strategy for the synthesis of complex molecules. Herein, an efficient palladium-catalyzed Heck/Suzuki tandem reaction of (Z)-1-iodo-1,6-dienes with organoboronic acids is described, providing various tetrahydropyridines in good to excellent yields under mild reaction conditions. The key to the success of this approach is the avoidance of the intramolecular second Heck insertion occurring prior to the transmetalation step. In addition, the asymmetric version of this reaction is investigated to deliver chiral tetrahydropyridine in excellent yield with promising enantioselectivity.

Palladium-catalyzed cascade cyclization of allenamide with 2-iodoanilines to access functionalized indoloquinolines

A novel and efficient palladium-catalyzed cascade cyclization to indoloquinoline derivatives in one pot has been developed by using allenamide derivatives and 2-iodoanilines as the key building blocks. The process involved two cyclizations: intramolecular cyclization/π-allylic substitution and intramolecular 6-endo Heck cyclization. Furthermore, dihydrobenzofuro[2,3-b]quinoline derivatives could also be achieved via this strategy using allenyl ethers instead of allenamides. The readily available substrates, mild conditions, high efficiency and step economy make this strategy a promising method in the synthesis of polycyclic motifs.