Rapid Synthesis of Chiral Figure-Eight Macrocycles Using a Preorganized Natural Product-Based Scaffold
Tasuku Honda1, Daiji Ogata2, Makoto Tsurui3
1Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Angewandte Chemie (International Ed. in English)
|January 3, 2024
Summary
Chiral figure-eight macrocycles amplify chiroptical properties. A new modular synthesis platform rapidly creates diverse chiral macrocycles with high circularly polarized luminescence brightness, eliminating optical resolution needs.
Area of Science:
- Organic Chemistry
- Materials Science
- Supramolecular Chemistry
Background:
- Chiral macrocycles are crucial for amplifying chiroptical properties in π-conjugated systems.
- Developing efficient synthetic routes for chiral macrocycles is essential for their application.
Purpose of the Study:
- To develop an enantio-divergent modular synthetic platform for chiral D2-symmetric figure-eight macrocycles.
- To rapidly generate diverse chiral macrocycles without optical resolution.
- To enhance circularly polarized luminescence (CPL) brightness.
Main Methods:
- Utilized a chiral C2-symmetric bispyrrolidinoindoline (BPI) manifold for adaptable conformational dynamics.
- Employed quadruple Sonogashira couplings for precise chromophore arrangement.
- Generated macrocycles ranging from 14 to 66-membered rings.
Main Results:
- Successfully synthesized a diverse range of chiral macrocycles.
- A 32-membered figure-eight macrocycle exhibited excellent CPL (|g_lum|=1.1×10⁻²), high emission quantum yield (Φ_fl=0.74), and outstanding CPL brightness (B_CPL=480).
- Demonstrated precise control over chromophore angle, distance, and length.
Conclusions:
- The developed synthetic platform is versatile and efficient for creating chiral macrocycles.
- This strategy significantly enhances CPL brightness in D2-symmetric figure-eight macrocycles.
- The platform streamlines the synthesis of advanced chiral materials.
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