Synthesis of 2,2,5-Trisubstituted 2H-Pyrroles and 2,3,5-Trisubstituted 1H-Pyrroles by Ligand-Controlled Site-Selective Dearomative C2-Arylation and Direct C3-Arylation.

Palladium-catalyzed site-selective dearomative C2-arylation of 2,5-diaryl-1H-pyrroles with aryl chlorides was accomplished, and a series of 2,2,5-triaryl-2H-pyrroles were synthesized. In addition, the site selectivity of the reaction was switched by simply changing the ligand, and the direct C3-arylated 2,3,5-triaryl-1H-pyrroles were prepared. The obtained 2,2,5-triaryl-2H-pyrroles could be further transformed into 2,2,5,5-tetraarylpyrrolidines.