Direct intramolecular oxidative functionalization, palladium-catalyzed

The formation of several 2-aminobenzothiazoles via palladium-catalyzed, direct intramolecular oxidative C-H functionalization was recently demonstrated by Batey at the University of Toronto. The substrates used were A -aryl thioureas which in the presence of an interesting co-catalytic Pd(PPh3)4/Mn02 system under oxygen atmosphere, yielded the desired products. In terms of the mechanism, this transformation proceeded presumably through electrophilic palladation, suggested by the higher reactivity of the more electron-deficient substrates. 

A direct and easy palladium-catalyzed C-H bond oxidative cyclization for the synthesis of polycyclic aromatic hydrocarbons (PAHs) was reported. The intramolecular palladium-catalyzed direct oxidative C-H bond functionalization for the C-O bond formation was demonstrated, which... 

Palladium-catalyzed Direct Arylation of Indoles and Thiophenes. Five-membered ring heterocycles possessing only one heteroatom and no Af-oxide function can also be arylated using palladium(II) complexes, a phosphine ligand, and an inorganic base. In one example, a tandem palladium-catalyzed Heck coupling reaction and direct intramolecular C2 arylation reaction on a )V-(2-chlorobenzyl)-5-bromoindole was reported (eq 30). The procedure, which is catalyzed by palladium acetate, uses tn-tert-butylphosphonium tetrafluoroborate as a ligand and ferf-butyl acrylate as the alkene for the Heck reaction (eq 30). ... 

---