Phenanthrene-Based Triptycenes: Synthesis and Cascade Skeletal Transformations

Area of Science:

• Organic Chemistry
• Supramolecular Chemistry
• Computational Chemistry

Background:

• Triptycenes are rigid, three-dimensional aromatic molecules with unique structural properties.
• Previous synthetic methods for triptycenes were limited, particularly for incorporating phenanthrene units.
• The development of new triptycene derivatives is crucial for advanced materials and molecular architectures.

Purpose of the Study:

• To report novel phenanthrene-based triptycene derivatives.
• To explore and optimize synthetic routes for triptycene framework construction.
• To investigate the reactivity and transformation of new dibenzotriptycenes.

Main Methods:

• Comparative Density Functional Theory (DFT) studies to guide reaction condition optimization.
• Cycloaddition reactions involving anthracene and various alkynes.
• Oxidative and electrophilic conditions (using PIFA and Br2) to induce skeletal transformations.

Main Results:

• Successful synthesis of novel phenanthrene-based triptycenes.
• Demonstrated successful cycloaddition reactions with both highly reactive arynes and normal alkynes.
• Observed cascade skeletal transformations of dibenzotriptycenes under oxidative and electrophilic conditions.
• Formation of synthetically challenging indenophenanthrene products.

Conclusions:

• The study presents new phenanthrene-based triptycenes with tunable synthetic access.
• The optimized cycloaddition methods expand the scope of triptycene synthesis.
• The novel dibenzotriptycenes exhibit interesting reactivity, yielding complex polycyclic aromatic hydrocarbons.