An efficient synthesis of highly functionalized asymmetric porphyrins withorganolithium reagents

Functionalized tri- (A(2)B-type) and tetra- (A(2)BC-type) meso-substituted asymmetric porphyrins bearing highly reactive centers like -NH2, -OH, -C=CH , -CHO in substituents at the meso positions were synthesized in good yield s via the reaction of 5,15-diphenylporphyrin with corresponding functionali zed organolithium reagents. Through further transformation other functional groups like carboxylate, iodophenyl, thiocarboxylate, tertiary amines and quaternary ammonium salts are easily available. Such porphyrins serve as pr ecursors for highly complex tetrapyrrolic systems. As examples, several nov el porphyrins with potentially useful chemical and physical properties such as amphiphilicity, water solubility, and electrochemical redox activity we re synthesized. In contrast to existing methods such compounds are now acce ssible regioselectively via one-step or two-step reactions in high yields. In addition, protocols were developed to prepare porphyrins with meso-aryl substituents bearing functional groups at the para, meta, or ortho position . Thus, starting materials for various specifically superstructured tetrapy rroles are available via rational syntheses.