Palladium-Catalyzed Multiple Arylation of Thiophenes
摘要:
Secondary 2-thiophenecarboxamides efficiently undergo unique triarylation accompanied by formal decarbamoylation under palladium catalysis. 3-Substituted thiophenes, especially having an electron-withdrawing group, can also be triarylated.
The first palladium‐catalyzed direct benzylic C(sp3)−H chalcogenation with diaryl disulfides and diphenyl diselenide has been established. The coupling reaction proceeds between the thioether radical and palladiumcycle intermediate. Picolinamide serves as an excellent directing group for the C−H activation of benzylic C(sp3)−H and can be easily removed. The current protocol exhibits a relatively
Secondary 2-thiophenecarboxamides efficiently undergo unique triarylation accompanied by formal decarbamoylation under palladium catalysis. 3-Substituted thiophenes, especially having an electron-withdrawing group, can also be triarylated.
Barbieri, Cristina Lea; Ceraulo, Leopoldo; Maria, Paolo De, Heterocycles, 1991, vol. 32, # 5, p. 975 - 984
作者:Barbieri, Cristina Lea、Ceraulo, Leopoldo、Maria, Paolo De、Fontana, Antonella、Spinelli, Domenico、Zuppiroli, Luca