Secondary Amides as ortho-Directed Metallation Groups for Arenes; a Useful Construction Way of the Polysubstituted Aromatic and Heteroaromatic Systems

The lithiation electrophilic substitution sequence of aromatic compounds has become very a common methodology for ortho-introduction of a long list of substituents in general. In particular, it was centered around the orthosubstitution of aromatic carboxylic acids via their masked forms. Till now, long list of reviews concerning tertiary amides or oxazolines as directing groups has been referred. On the other hand, secondary amides, even historically first masked function of aromatic carboxylic acids, were discussed in much smaller extent. In here, the scope of this methodology and the application of the secondary amide function in organic synthesis is presented.