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DOI: 10.1055/a-2627-8429
Towards Strained Pillar[4]arene Derivatives
Supported by: Initiative Scientific Research Program, Tsinghua University
Supported by: Tsinghua University
Supported by: Zhejiang University
Supported by: Dushi Program
Supported by: National Natural Science Foundation of China 22193020,22193022,22371251

Over the past decade, pillar[n]arenes have emerged as prominent macrocyclic hosts in supramolecular chemistry owing to their straightforward synthesis, versatile functionalization, and rigid columnar cavities, attracting considerable research interest. However, conventional Lewis acid-catalyzed cyclizations exhibit an inherent preference for larger pillar[n]arenes (n ≥ 5) due to kinetic and thermodynamic factors associated with the dynamic oligomerization process, thereby precluding the synthesis of strained pillar[4]arene architectures. In order to overcome this challenge, we developed an innovative strain-engineering strategy—from low to high strain—based on a key thiophene-to-benzene transformation. This approach involves stepwise thiophene oxidation followed by an inverse electron- demand Diels–Alder (IEDDA) reaction, dynamically driven by SO₂ extrusion. High-resolution mass spectrometry confirmed the formation of tetrahydro-pillar[4]arene derivatives in the reaction mixture through their characteristic isotopic patterns. Our work establishes a viable route to challenging strained pillar[4]arenes.
Publication History
Received: 03 May 2025
Accepted after revision: 04 June 2025
Accepted Manuscript online:
04 June 2025
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