Site-Selective Binding of Peripheral Chiral Guests Induces Stereospecificity in A₄L₆ Tetrahedral Anion Cages

Herein we report an unprecedented chiral induction of anion-coordination-driven tetrahedra (A₄L₆-type) by peripheral guests, S-, R-α-methylcholine and S-, R-β-methylcholine, which are bound along the tetrahedral edges in a highly site-specific fashion. This "peripheral templation", which has proven indispensable for the formation of tetrahedral structure, is also an effective approach to encoding chiral information to the tetrahedron. Moreover, the site-selective binding of chiral choline derivatives to the anion cage with induced one-handedness may imply applications of such metal-free, labile systems in the study of biological processes such as selective recognition of structurally similar molecules.