Fused ring construction around pyrrole, indole, and related compounds via palladium-catalyzed oxidative coupling with alkynes.
The selective synthesis of 1,2,3,4-tetrasubstituted carbazoles can be performed effectively through the palladium-catalyzed oxidative coupling reactions of N-substituted indoles or their carboxylic acid derivatives with alkynes. Unsymmetrically octasubstituted carbazoles can also be obtained by the stepwise couplings of 1-methylpyrrole-2-carboxylic acid with two different alkynes. In addition, the present coupling procedure is applicable to the synthesis of other various heteroarenes possessing di-, tri-, and tetracyclic cores. Some of the products exhibit intense fluorescence in the solid state.
Yamashita
Mana
M
Department of Applied Chemistry, Faculty of Engineering, Osaka University, Suita, Osaka 565-0871, Japan.
Horiguchi
Hakaru
H
Hirano
Koji
K
Satoh
Tetsuya
T
Miura
Masahiro
M
D000480:Alkynes / Q000737:chemistry*; D002264:Carboxylic Acids / Q000737:chemistry; D002384:Catalysis; D003500:Cyclization; D007211:Indoles / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010165:Palladium / Q000737:chemistry*; D011758:Pyrroles / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
D000480:Alkynes; D002264:Carboxylic Acids; D007211:Indoles; D011758:Pyrroles; D010165:Palladium