Simple Porphyrin Desymmetrization: 5,10,15,20‐Tetrakis(3‐hydroxyphenyl)porphyrin (mTHPP) as a Gateway Molecule for Peripheral Functionalization

Abstract

AbstractThe rise in the demand of unsymmetrical porphyrin systems for applications such as photodynamic therapy and nonlinear optics mandates a concomitant development of simple and practical synthetic approaches. A new method for the rapid generation of unsymmetrical porphyrins from the same common and easily accessible symmetric porphyrin starting material is discussed herein. A library of unsymmetric mTHPP [5,10,15,20‐tetrakis(3‐hydroxyphenyl)porphyrin] derivatives were synthesized in good yields through simple nucleophilic substitution, esterification, and metal‐catalyzed cross‐coupling reactions. This method was optimized to generate a library of customized unsymmetrical porphyrins quickly for use in a variety of applications. A common meso‐aryl‐substituted porphyrin as the starting material was used to update the synthetic toolkit through a mixture of classical and modern chemistry. This approach was studied as an approach to the synthesis of picket fence porphyrin mimics and afforded such compounds in good yields with few synthetic steps. In addition, employing simple nucleophilic substitution chemistry was employed to access cofacial caged bis(porphyrin) systems in two synthetic steps.