Catalytic Enantioselective Synthesis of Planar Chiral Pillar[5]arenes via Dynamic Kinetic Resolution
Xiao-Hua Zhou, Wei Wang
Abstract
Pillar[n]arenes are a class of emerging supramolecular macrocyclic hosts that have attracted significant attention due to their intriguing dynamic planar chirality and unique cavity structures. In particular, the conformation of pillar[5]arenes can be locked by the introduction of bulky substituents or π-conjugated units at both rims, resulting in stable planar chirality. This strategy paves the way for the application of planar chiral pillar[5]arenes as versatile chiral molecular platforms. In recent years, planar chiral pillar[5]arenes have been widely applied in various research fields, such as chiral porous materials, chiral luminescent materials, and molecular machines. However, obtaining planar chiral pillar[5]arenes in enantiomeric forms remains a significant challenge. Recently, asymmetric catalytic synthesis via dynamic kinetic resolution (DKR) has proven to serve as a powerful tool for the efficient preparation of planar chiral pillar[5]arenes, which allows for achieving high levels of enantioinduction while producing a series of functionalized planar chiral pillar[5]arenes. This concept summarizes these achievements and highlights the design principles and key challenges, aiming to provide valuable insights for future research.