Functional [6]pericyclynes: synthesis through [14+4] and [8+10] cyclization strategies

Area of Science:

• Organic Chemistry
• Supramolecular Chemistry
• Synthetic Methodology

Background:

• Carbo-benzene derivatives and pericyclynes are of interest in materials science and medicinal chemistry.
• Previous synthetic efforts for hexaoxy[6]pericyclynes were limited, necessitating exploration of new strategies.
• The development of efficient and selective synthetic routes is crucial for accessing novel molecular architectures.

Purpose of the Study:

• To critically analyze and explore novel [(18-n)+n] synthetic strategies for hexaoxy[6]pericyclyne precursors.
• To investigate the efficiency and scope of [14+4] and [8+10] strategies as alternatives to previously used methods.
• To synthesize and characterize novel hexaoxy[6]pericyclyne derivatives with diverse substitution patterns.

Main Methods:

• Utilized a cyclizing double-propargylation approach involving C(18-n) and C(n) omega-skipped oligoyne precursors.
• Explored and implemented [14+4] and [8+10] synthetic strategies.
• Employed dibenzoylacetylene and hexacarbonyldicobalt complex of butynedial as electrophilic components.

Main Results:

• Successfully synthesized seven novel hexaoxy[6]pericyclynes across six distinct substitution patterns.
• The [14+4] strategy yielded hexaphenyl and tetraphenyl derivatives with varying degrees of substitution.
• The [8+10] strategy provided access to regioisomers and fragile diphenyl derivatives, highlighting synthetic challenges.

Conclusions:

• The explored [(18-n)+n] strategies, particularly [14+4] and [8+10], are efficient for synthesizing diverse hexaoxy[6]pericyclynes.
• The synthesis of the non-substituted hexahydroxy[6]pericyclyne remains a significant challenge.
• This work expands the accessible chemical space of pericyclyne derivatives for future applications.