Convenient generation of a directing group on the nitrogen of indoles is possible through treatment with an organolithium reagent and carbon dioxide. A similar method can be applied for lateral lithiations of ortho-tolyl anilines.
Oxazoles containing two methyl groups exhibit interesting selectivity patterns. In the absence of a directing substituent, the methyl group closer to the more electronegative oxygen atom is selectively metalated. However, in the presence of a directing substituent, the director fully controls the site of lithiation.