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 desulfurization 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(η2-C,S-C12H8)] (4) was used as a catalyst precursor to test its participation as an active intermediary in the catalytic cycle.