Supported palladium hydroxide-catalyzed intramolecular double CH bond functionalization for synthesis of carbazoles and dibenzofurans
•Pd(OH)2/ZrO2 catalyzed intramolecular coupling of double CH bonds to form CC bonds.•Carbazoles and dibenzofurans were obtained over Pd(OH)2/ZrO2 with high selectivity.•Pd(OH)2/ZrO2 could be recycled.
Metal oxide-supported palladium hydroxide (Pd(OH)2/MOx) catalysts enabled the oxidative intramolecular couplings of diarylamines to carbazoles and diarylethers to dibenzofurans via double aryl CH bond functionalizations with molecular oxygen as the sole oxidant. While supported PdO, Pd, and palladium acetate catalysts showed poor catalytic activities, supported Pd(OH)2 exhibited remarkably high catalytic activity. Among supported Pd(OH)2 catalysts, Pd(OH)2/ZrO2 was found to be an efficient catalyst in terms of catalytic activities and selectivities for the synthesis of carbazoles and dibenzofurans.
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Journal: Applied Catalysis B: Environmental - Volumes 150–151, 5 May 2014, Pages 523–531