Face-selective adsorption of a prochiral compound on the chiral pore-surface of metal-macrocycle framework (MMF) directed towards stereoselective reactions
Molecular adsorption on a surface is a unique way to break the mirror-symmetry of prochiral molecules, and therefore the use of chiral surfaces is an effective strategy for achieving highly selective chiral separation and asymmetric catalytic reactions based on the molecular adsorption with high diastereoselectivity. We have previously reported a porous metal-macrocycle framework (MMF) having an enantiomeric pair of chiral pore-surfaces derived from PdII3-helical macrocycles as the ingredients of the framework. Aiming at applying the chiral pore-surface of MMF to asymmetric reactions and chiral separation, herein we propose a strategy to utilize one of the enantiomerically paired pore-surfaces as a homochiral pore-surface with the aid of chiral auxiliaries that can block only one side of the enantiomeric pore-surfaces in a site-selective manner. Single-crystal X-ray diffraction analysis revealed that a chiral auxiliary, (1R)- or (1S)-1-(3-chlorophenyl)ethanol, and a prochiral guest molecule, 2'-hydroxyacetophenone, were cooperatively arranged in each unit pore so that the prochiral guest molecule can face-selectively bind to the homochiral pore-surface.
- This article is part of the themed collection: Cooperative phenomena in framework materials