Synthesis of unsymmetrical carboxyphthalocyanines by palladium-catalyzed hydroxycarbonylation of iodo-substituted precursors.

Phthalocyanines (Pcs) containing a carboxylic acid functionality directly bound to the macrocycle have been synthesized, in one step and in good yields, from iodo-substituted Pc precursors. This methodology represents a convenient alternative to the commonly used method based on two consecutive oxidations of hydroxymethyl Pcs.