Synthesis of 5,10,15,20-Tetrakis(4-tert- butyl-2,6-dicarboxyphenyl)porphyrin: A Versatile Bis-Faced Porphyrin Synthon forD4-Symmetric Chiral Porphyrins

[see structure]. A versatile bis-faced porphyrin synthon, 5,10,15,20-tetrakis(4-tert-butyl-2,6-dicarboxyphenyl)porphyrin, was synthesized. The eight carboxyl groups were readily converted into various amide groups, and condensation with chiral amines led to various D4-symmetric chiral porphyrins with rigid structures.