Synthesis of Dibenzofurans via Palladium-Catalyzed Phenol-Directed C–H Activation/C–O Cyclization
摘要:
A practical, Pd(0)/Pd(II)-catalyzed reaction was developed for phenol-directed C-H activation/C-O cyclization using air as an oxidant. The turnover-limiting step of the process was found to be C-O reductive elimination instead of C-H activation. This reaction can tolerate a variety of functional groups and is complementary to the previous methods for the synthesis of substituted dibenzofurans.
Oxidative Cyclization of 2-Arylphenols to Dibenzofurans under Pd(II)/Peroxybenzoate Catalysis
摘要:
2-Arylphenols undergo intramolecular C-H bond activation/C-O bond formation to afford dibenzofuran derivatives under palladium catalysis In the presence of tert-butyl peroxybenzoate as an oxidant. Kinetic isotope effect experiments indicated that C-H bond cleavage Is the rate-limiting step of the reaction.