Calix[6]arene-based Brønsted acids for molecular recognition and catalysis

Area of Science:

• Supramolecular Chemistry
• Organic Synthesis
• Catalysis

Background:

• Calix[6]arene derivatives are known for their host-guest chemistry.
• Trifluoromethylsulfonamide groups can impart unique electronic and acidic properties.
• Developing catalysts for reactions under physiological conditions is a significant challenge.

Purpose of the Study:

• To synthesize a novel trifluoromethylsulfonamide calix[6]arene derivative.
• To investigate its capabilities in molecular recognition, specifically ion-pair recognition.
• To explore its potential as a Brønsted acid catalyst for organic transformations.

Main Methods:

• Synthesis of the trifluoromethylsulfonamide calix[6]arene derivative.
• Spectroscopic and analytical characterization of the compound.
• Evaluation of ion-pair recognition in low polarity media.
• Catalytic testing of Michael addition reactions under aqueous, 37°C conditions.

Main Results:

• Successful synthesis of the target calix[6]arene derivative.
• Demonstrated selective ion-pair recognition of charged species in non-polar environments.
• The derivative effectively catalyzed Michael additions of indoles to nitroalkenes.
• The catalytic activity was observed under pseudo-physiological conditions (water, 37°C).

Conclusions:

• The synthesized trifluoromethylsulfonamide calix[6]arene is a versatile molecule with dual functionality.
• It exhibits promising properties for both molecular recognition and catalysis.
• Its ability to perform catalysis in water at physiological temperatures opens avenues for green chemistry applications.