Divergence in Ynone Reactivity: Atypical Cyclization by 3,4-Difunctionalization versus Rare Bis(cyclization)

Area of Science:

• Organic Chemistry
• Heterocyclic Chemistry

Background:

• Ynones are versatile building blocks in organic synthesis.
• Triflones are sulfur-containing compounds with potential applications.

Purpose of the Study:

• To develop a novel synthetic route for triflone compounds.
• To explore the selective synthesis of fused heterocycles.

Main Methods:

• Activation of functionalized ynones using Tf2C=CH2 generated in situ.
• Intramolecular trapping of zwitterionic intermediates by nucleophiles.
• Control of reaction temperature for selective product formation.

Main Results:

• Successful synthesis of two major types of triflones.
• Selective formation of bis(triflyl)-6-membered or (triflyl)-5-membered fused heterocycles.
• Construction of various complex molecules including bis(triflyl)flavones and (triflyl)benzothienopyrans.

Conclusions:

• The developed method offers a divergent and selective pathway to synthesize diverse triflone derivatives.
• Temperature control is crucial for achieving selectivity in the formation of fused heterocyclic systems.
• The study provides insights into the mechanistic pathways of these transformations.