Reductive Amination-A convenient method for generating diverse, mono-functionalised 5,10,15,20-tetraphenyl porphyrins

Formylation followed by reductive amination of 5,10,15,20-tetraphenyl porphyrin (TPP) is shown to be a versatile synthetic procedure for monosubstitution of the porphyrin core re-giospecifically at one β-position. A diverse range of substituents can be introduced in this way in good yields, including cyclen aza-crown macrocycles. © Georg Thieme Verlag Stuttgart