Ring-expansion protocol: preparation of synthetically versatile dihydrotropones

Area of Science:

• Organic Chemistry
• Synthetic Chemistry

Background:

• Dihydrotropones are valuable synthetic intermediates.
• Efficient methods for their synthesis are crucial for accessing complex molecular architectures.

Purpose of the Study:

• To develop a novel ring-expansion protocol for the synthesis of dihydrotropones.
• To demonstrate the utility of dihydrotropones in constructing polycyclic compounds.

Main Methods:

• 1,2-addition of enolate nucleophiles to 6-trimethylsiloxy-2-cyclohexene-1-one.
• Sodium periodate (NaIO(4))-promoted oxidative ring opening of diols.
• Intramolecular Knoevenagel condensation.

Main Results:

• A versatile synthesis of dihydrotropones was achieved through a multi-step protocol.
• Maintaining Z-configuration during oxidative ring opening is critical for the strategy's success.
• The synthesized dihydrotropones were elaborated into tropones and polycyclic compounds via Diels-Alder reactions.

Conclusions:

• The developed ring-expansion protocol provides efficient access to dihydrotropones.
• Dihydrotropones are key intermediates for synthesizing diverse and complex organic molecules.