Regioselective Nucleophilic Aromatic Substitution Reaction of meso-Pentafluorophenyl-Substituted Porphyrinoids with Alcohols

A detailed study of the nucleophilic aromatic substitution reaction of meso-pentafluorophenyl-substituted tetrapyrrole systems with different alcohols is presented. The systematic investigation of various alcohols and bases in two different solvents led to optimized reaction conditions, allowing the selective substitution of the p-fluorine atoms of meso-pentafluorophenyl-substituted porphyrins, their zinc complexes, and a meso-tris(pentafluorophenyl) corrole with alcohols and a simple base in high yields. When applied to A(3)B porphyrins in combination with suitable protecting groups, functionalized, polar A(3)B porphyrins can be prepared in a simple two-step one-pot procedure. By using the nucleophilic aromatic substitution reaction, a dimeric porphyrin system was synthesized. In addition, the copper(I)-catalyzed 1,3-dipolar cycloaddition of properly functionalized meso-pentafluorophenyl-substituted porphyrins led to the corresponding porphyrin dimer with a 1,2,3-triazole linker. The method described herein allows a simple and fast approach towards multifunctionalized porphyrinoids based on meso-pentafluorophenyl- substituted tetrapyrroles.