Palladium-catalyzed 2-arylation of pyrroles.
A methodology that affords N-alkyl-2-arylpyrroles and N-aryl-2-arylpyrroles via direct coupling from aryl iodides has been developed. After examining various reaction parameters: solvent, ratio of reagents, catalyst, base and additives the optimal conditions for the condensation were identified. Two crucial factors, (a) anhydrous DMSO as solvent and (b) 5 M excess of pyrrole counterpart, were found to strongly influence the reaction outcome. The conditions identified (PdCl(2)(PPh(3))(2), AgOAc, anhyd DMSO, KF, 100 degrees C, 5 h) resulted in the formation of 2-arylpyrroles in 14-80% yield. Furthermore, the synthesis is compatible with electron-withdrawing and electron-donating groups on the aryl moiety.
Gryko
Daniel T
DT
Institute of Organic Chemistry of the Polish Academy of Sciences, Warsaw, Poland. daniel@icho.edu.pl
Vakuliuk
Olena
O
Gryko
Dorota
D
Koszarna
Beata
B
D002384:Catalysis; D004121:Dimethyl Sulfoxide / Q000737:chemistry; D006844:Hydrocarbons, Cyclic / Q000138:chemical synthesis / Q000737:chemistry*; D006847:Hydrocarbons, Iodinated / Q000737:chemistry; D008956:Models, Chemical; D009942:Organometallic Compounds / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry*; D011758:Pyrroles / Q000138:chemical synthesis / Q000737:chemistry*; D012834:Silver / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D013696:Temperature; D013997:Time Factors
D006844:Hydrocarbons, Cyclic; D006847:Hydrocarbons, Iodinated; D009942:Organometallic Compounds; D011758:Pyrroles; D012997:Solvents; D012834:Silver; D010165:Palladium; D004121:Dimethyl Sulfoxide