A method for Pd-catalyzed aerobic oxidative reaction of quinazolinones and alkynes has been developed for sequential [4 + 2] and [3 + 2] cycloadditions to assemble a novel fused-polycyclic system containing tetrahydropyridine and dihydrofuran rings. The reaction process involves C-H and N-H bond functionalization for the formation of tetrahydropyridine and an oxygen radical cyclization for the dihydrofuran ring. This atom- and step-economical synthesis is highly efficient and has good substrate tolerance, which provides a new approach for the construction of polycyclic molecules with potential pharmaceutical interest.

A novel copper-catalyzed synthesis of quinazolinones from easily available 2-arylindoles and amines or ammoniums has been developed, which provided various quinazolinones in up to 99% yields for 43 examples. This strategy features tolerance of a wide range of functional groups, easily available starting materials, simple operation, mild reaction conditions, and environmental friendliness.

A novel Ir-catalyzed annulation of imidamides with sulfonyl azides has been developed. 1,2-Disubstituted benzimidazoles could be easily obtained in up to 99% yield for more than 40 examples. The products further streamline the synthesis of molecules that are important building blocks for organic synthesis and drug discovery. This strategy features high regioselectivity, efficiency, good tolerance of functional groups, and mild reaction conditions.

An efficient hydroamidation of benzylamides with internal alkynes catalyzed by Ru­(II) has been developed. Various (E)-enamides were afforded in up to 95% yield for 28 examples. The protocol features excellent regio- and stereoselectivity, widely functional group tolerance, and easily accessible starting materials.

No abstract