Ortho-hydroxy aromatic stabilizers

Sections D through H of Scheme 3.2 involve oxygen nucleophiles. The hydrolysis reactions in Entries 12 and 13 both involve benzylic positions. The reaction site in Entry 13 is further activated by the ERG substituents on the ring. Entries 14 to 17 are examples of base-catalyzed ether formation. The selectivity of the reaction in Entry 17 for the meta-hydroxy group is an example of a fairly common observation in aromatic systems. The ortho-hydroxy group is more acidic and probably also stabilized by chelation, making it less reactive. 

Lajunen, L.H.J. Portanova, R. Piispanen, J. Tolazzi, M. Critical evaluation of stability constants for alpha-hydroxycarboxylic acid complexes with protons and metal ions and the accompanying enthalpy changes. Part I. Aromatic ortho-hydroxy carboxylic acid. PureAppl. Chem. 1997, 69 (2), 329-381. 

It means that the increase of stabilization of chelate chain is associated with a decrease of aromaticity, i.e., Tr-electron delocalization in the ring. A similar situation was observed for the first X-ray determined ionic H-bonding in the crystal state for ortho-hydroxy Schiff base—5-nitro-A-salicylideneethylamine... 

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