Supramolecular Catalysis of the oxa‐Pictet–Spengler Reaction with an Endohedrally Functionalized Self‐Assembled Cage Complex

An endohedrally functionalized self‐assembled Fe4L6 cage complex can catalyze oxa‐Pictet—Spengler cyclizations of tryptophols and various aldehyde derivatives, showing strong rate accelerations and size‐selectivity. Selective molecular recognition of substrates controls the reactivity, and the cage is capable of binding and activating multiple different species along the multistep reaction pathway. The combination of a functionalized active site, size‐selective reactivity, and multistep activation, all from a single host molecule, illustrates the biomimetic nature of the catalysis. An endohedrally functionalized self‐assembled Fe4L6 cage complex can catalyze oxa‐Pictet–Spengler cyclizations of tryptophols and various aldehyde derivatives. The combination of a functionalized active site, size‐selective reactivity, and multistep activation, all from a single host molecule, illustrates the biomimetic nature of the catalysis.