Stereospecific Assembly of Triply Chiral Pseudopeptidic Cages Through Dynamic Dual Chirality Transfer

Abstract

ABSTRACT A stereospecific transmission of chiral information within tripodal pseudopeptidic cages has been observed from dynamic constitutional co‐operation of reversible orthogonal processes: imine bond and metal coordination. The chiral centers from the phenylalanine amino acid moieties induce a specific chirality into the formed octahedral Fe(II) complex and into the helical twist of the macrobicycle, as confirmed by NMR, circular dichroism, X‐ray diffraction of single crystals, and theoretical calculations. Instead, when a configurationally stable Ru(II) complex is employed, the dynamic imine exchange efficiently selects the corresponding matched‐combination of the same chiral elements, leading after reduction to a water‐soluble homochiral stable macrobicyclic pseudopeptide Ru(II) complex with appealing chemical and photophysical properties. Overall, our study demonstrates how subtle structural factors from a chiral effector in a reversible dynamic system rule the generation and selection of subsequent chiral elements with high fidelity and complete stereocontrol.