Synthesis, binding properties and self-functionalization of a steroid-capped porphyrin

A porphyrin capped with a steroidal superstructure bearing convergent hydroxy groups has been synthesized and shown to bind a variety of functionalized amines via a combination of metal–amine and hydrogen-bonding interactions; the metal–ligand interaction was used to catalyse and control selective acylation of a single hydroxy group in the cap.