Propane activation by palladium complexes with chelating bis(NHC) ligands and aerobic cooxidation.
The development of efficient aerobic oxidation methods remains a challenge for the selective functionalization of C-H bonds in alkanes. Herein we report the development of a C-H functionalization procedure for propane by using a palladium catalyst with chelating bis(N-heterocyclic carbene) ligands in trifluoroacetic acid together with a vanadium co-catalyst. Halides play a decisive role in the reaction. The experimental results are presented together with supporting kinetic data and an isotope effect. The reaction can be run with dioxygen as the oxidant if vanadium salts and halides are present in the reaction mixture. Experimental as well as computational results favor a mechanism involving C-H activation by palladium(II), followed by oxidation to palladium(IV) by bromine.
Physikalische Organische Chemie, Technische Universität Dresden, 01069 Dresden (Germany).
Dominik
D
Munz
Thomas
T
Strassner
CH activation; oxygen; palladium; reaction mechanisms; vanadium