Iridium indole synthesis

Scheme 5 Iridium-Based Watanabe Indole Synthesis...

Catellani [61] reported a palladium/norbomene-catalyzed synthesis of heteroatom-containing o-teraryls from aryl iodides and heteroarenes (including indoles and pyrroles) through double C-H arylation. Fagnou s group [62] applied their own protocol (Pd(II)/Ag(I)/carboxylic acid) to achieve the direct arylation of azaindoles. Itami [63] demonstrated the first iridium-catalyzed C-H arylation of heteroarenes (involving indoles and pyrroles) with aryl halides. 

Messerle and coworkers reported that a cationic iridium(lll) complex with a methyl-bridged bipyrazoyl or pyrazoyl-l,2,3-triazole (N-N) ligand [lr(N-N)Cp Cl] B Ar 4 (B Ar ".j = tetrakis[3,5-bis(trifluoromethyl)phenyl]borate) had catalytic activity for the synthesis of tricyclic indoles [161]. The process... 

---