A fragment-based approach toward substituted trioxa[7]helicenes

Area of Science:

• Organic Chemistry
• Supramolecular Chemistry
• Materials Science

Background:

• Helicenes are chiral aromatic compounds with unique 3D structures.
• Developing efficient synthetic routes for substituted helicenes is crucial for exploring their properties.
• Dibenzofuran derivatives offer versatile building blocks for complex molecular architectures.

Purpose of the Study:

• To synthesize novel substituted trioxa[7]helicenes.
• To investigate the crystal structure and supramolecular assembly of these helicenes.
• To explore the utility of palladium-catalyzed C-H arylation for helicene synthesis.

Main Methods:

• One-pot palladium-catalyzed C-H arylation reaction.
• Synthesis starting from dibenzofuran fragments.
• X-ray crystallography for structural analysis.

Main Results:

• Successful preparation of a series of novel substituted trioxa[7]helicenes.
• Identification of two distinct enantiomers in the asymmetric unit of the dinitro-substituted helicene.
• Observation of interesting supramolecular motifs driven by weak hydrogen bonding in the crystal.

Conclusions:

• Palladium-catalyzed C-H arylation is an effective method for synthesizing trioxahelicenes.
• The dinitro-substituted helicene exhibits enantiomeric diversity and forms unique crystal packing.
• This work expands the scope of helicene synthesis and provides insights into their supramolecular chemistry.