Alkene 1,3-Difluorination via Transient Oxonium Intermediates

Area of Science:

• Organic Chemistry
• Fluorine Chemistry
• Synthetic Methodology

Background:

• 1,3-difunctionalization of unactivated alkenes is synthetically challenging.
• Accessing 1,3-difluoro-4-oxy moieties is difficult using existing methods.

Purpose of the Study:

• To develop a novel hypervalent iodine-mediated 1,3-difluorination of homoallylic (aryl) ethers.
• To synthesize previously unreported 1,3-difluoro-4-oxy groups with control over stereochemistry.

Main Methods:

• Utilized hypervalent iodine reagents for alkene difluorination.
• Investigated a unique reaction mechanism involving oxonium intermediates and alkyl chain rearrangement.
• Optimized reaction conditions for scalability and substrate scope.

Main Results:

• Achieved moderate to excellent diastereoselectivity in the formation of 1,3-difluoro-4-oxy products.
• Demonstrated the scalability of the optimized protocol.
• Showcased broad functional group tolerance and compatibility with various substitutions on the alkenyl chain.

Conclusions:

• The developed method provides efficient access to valuable 1,3-difluoro-4-oxy moieties.
• The reaction proceeds via a novel 1,3-difunctionalization pathway.
• This work expands the synthetic toolbox for creating complex fluorinated organic molecules.