Catalytic desulfurization of dibenzothiophene and 4,6-dimethyldibenzothiophene with nickel compounds

Catalytic amounts of the compounds [(dippe)NiH](2) (1), [(dcpe)NiH](2) (2), and [Ni(PEt3)(4)] (3) (1-0.1 mol %) with alkyl Grignard reagents promoted the desulfarization of dibenzothiophene, 4-methyldibenzothiophene, and 4,6-dimethyldibenzothiophene, to produce the corresponding biphenyls (90-100%) in toluene or mixtures of biphenyls and thiols favored in THF. Also, the thianickelacycle [(dippe)Ni(eta(2)-C,S-C12H8)] (4) was used as a catalyst precursor to test its participation as an active intermediary in the catalytic cycle.