Cationic polycyclization of ynamides: building up molecular complexity.

Area of Science:

• Organic Chemistry
• Synthetic Chemistry
• Heterocyclic Chemistry

Background:

• Polycyclization reactions are crucial for synthesizing complex molecular architectures efficiently.
• Developing new synthetic methodologies for polycyclic compounds remains a key challenge in organic chemistry.

Purpose of the Study:

• To report the discovery and development of a novel cationic polycyclization reaction.
• To utilize readily available ynamides as starting materials for this transformation.

Main Methods:

• Activation of ynamides under acidic conditions to generate keteniminium ions.
• Exploration of the subsequent cationic polycyclization cascade.

Main Results:

• The developed method enables the synthesis of highly substituted polycyclic nitrogen heterocycles.
• The reaction yields complex structures with up to seven fused cycles.
• Formation of three contiguous stereocenters is achieved in a single step.

Conclusions:

• This novel cationic polycyclization of ynamides offers an efficient route to complex nitrogen heterocycles.
• The method provides access to intricate molecular scaffolds with valuable stereochemical features.