Lithiation of 2, 5-dibromothiophene by LDA with ensuing silylation proceeds regiospecifically in accordance with the halogen dance mechanism to yield 3, 5-dibromo-2- trimethylsilylthiophene or 3, 4-dibromo-2, 5-bis (trimethylsilyl) thiophene depending on the ratio of reagents. The outcome of the reaction was confirmed by further chemical transformations of the latter compound to 2, 5-bis (trimethylsilyl) thiophene and 2, 5-bis ( ...
