Active-alkali metal promoted reductive desulfurization of dibenzothiophene and its hindered analogues

Dibenzothiophene and some related organosulfur compounds are efficiently reductively desulfurized under mild reaction conditions, with Na and/or Li metal in the presence of a catalytic amount of tetraphenylethylene in THF at room temperature. This simple methodology was applied to the synthesis of several substituted biphenyls, thus realizing a connection between the directing properties of the sulfur atom of dibenzothiophene and the efficiency of 1,2-dianions of tetraphenylethane as homogenous electron transfer reagents.