An efficient synthesis of highly functionalized asymmetric porphyrins with organolithium reagents

摘要

Functionalized tri- (A2B-type) and tetra- (A2BC-type) meso-substituted asymmetric porphyrins bearing highlynreactive centers like -NH2, -OH, -Cu0001u0001 u0001CH, -CHO in substituents at the meso positions were synthesized in goodnyields via the reaction of 5,15-diphenylporphyrin with corresponding functionalized organolithium reagents.nThrough further transformation other functional groups like carboxylate, iodophenyl, thiocarboxylate, tertiarynamines and quaternary ammonium salts are easily available. Such porphyrins serve as precursors for highly complexntetrapyrrolic systems. As examples, several novel porphyrins with potentially useful chemical and physical propertiesnsuch as amphiphilicity, water solubility, and electrochemical redox activity were synthesized. In contrast to existingnmethods such compounds are now accessible regioselectively via one-step or two-step reactions in high yields. Innaddition, protocols were developed to prepare porphyrins with meso-aryl substituents bearing functional groupsnat the para, meta, or ortho position. Thus, starting materials for various specifically superstructured tetrapyrrolesnare available via rational syntheses.