C-H-Activated ortho-Arylation of Anilides and Their Cyclization to Phenanthridines

Significance

An efficient synthesis of 2-aryl- and 2,6-diarylanilides is reported utilizing a palladium-catalyzed direct arylation of N-acyl anilines with various aryl iodides. A steric component is evident in this interesting reaction since ortho-substituted aryl iodides failed. Deacylation using NaOH (3 examples, 85-99% yields) led to the corresponding anilines while trifluoroacetic anhydride afforded phenanthridines. The reaction was run also in one pot, without the need to isolate the intermediate coupling products. In general, the substrate scope was well studied.