Step Cyclization to Give Part Belt Oxygen-Functionalized Pillar[6,10]arenes

Area of Science:

• Supramolecular Chemistry
• Organic Synthesis
• Macrocyclic Chemistry

Background:

• Pillararenes are a class of macrocyclic compounds with a unique cyclic structure.
• Functionalization of pillararenes can alter their properties and applications.
• Understanding structural variations is key to designing new macrocyclic hosts.

Purpose of the Study:

• To synthesize novel part belt oxygen-functionalized pillar[6,10]arenes.
• To investigate the structural characteristics and differences compared to traditional pillararenes.
• To explore the utility of step cyclization for constructing complex macrocycles.

Main Methods:

• Step cyclization reactions were employed for synthesis.
• Preparation of oxygen-substituted tetramer and hexamer precursors.
• X-ray crystallography and variable-temperature 1H NMR spectroscopy for structural analysis.

Main Results:

• Successful synthesis of O3 pillar[6]arene 4 and O6 pillar[10]arene 7.
• X-ray crystallography confirmed large cavities and distinct configurations.
• NMR studies highlighted structural differences from traditional pillararenes.

Conclusions:

• Part belt oxygen-functionalized pillar[6,10]arenes possess unique cyclic structures and configurations.
• These novel macrocycles offer structural diversity compared to conventional pillararenes.
• The synthetic strategies provide a pathway for creating tailored macrocyclic architectures.