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Abstract
We have developed a convenient solvent‐ and catalyst‐free selective Mannich reaction of a variety of para‐substituted phenols or catechols with paraformaldehyde and ethyl iminodiacetate. With para‐substituted phenols and electron‐poor catechol, only the monosubstituted benzyliminodiacetic ester is selectively formed in good yield and no disubstituted product is detected. In contrast, electron rich catechols gave mono‐ or disubstituted derivatives depending on the stoichiometry of ethyliminodiacetate. Furthermore, the reaction is highly regioselective with catechols, since no para derivatives are formed. In addition, we describe a mild acidic hydrolysis of the ester functions, which avoids the degradation of the benzylamine moiety by the quinone methide pathway. So, pure o‐hydroxybenzyliminodiacetic acid ligands are obtained in overall good yields.