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Mechanistic Insights into the C–S Bond Breaking in Dibenzothiophene Sulfones

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journal contribution
posted on 2012-05-28, 00:00 authored by Alberto Oviedo, Alma Arévalo, Marcos Flores-Alamo, Juventino J. García
The reactivity of Grignard reagents in the presence of nickel catalysts is known to be highly efficient in the deoxydesulfurization of dibenzothiophene sulfone (DBTO2), 4-methyldibenzothiophene (4-MeDBTO2), and 4,6-dimethyldibenzothiophene (4,6-Me2DBTO2), to yield sulfur-free biphenyls via cross-coupling reactions. However, the mechanistic details involved in the process remained unknown. In this report the reactivity of [(dippe)­Pt­(μ-H)]2 with DBTO2 turned out to be catalytically less efficient compared with [(dippe)­Ni­(μ-H)]2, but the first allowed the isolation and full characterization of several reaction intermediates, such as [(dippe)­Pt­(κ2-C,S-DBTO2)]. It was demonstrated that this is a key intermediate in all the deoxydesulfurization reactions of the above-mentioned aromatic sulfones (DBTsO2).

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