Copper-Catalyzed C-H Fluorination/Functionalization Sequence Enabling Benzylic C-H Cross Coupling with Diverse...

Area of Science:

• Organic Chemistry
• Catalysis
• Synthetic Methodology

Background:

• Benzylic C-H bonds are prevalent in organic molecules.
• Direct functionalization of C-H bonds offers atom-economical synthetic routes.
• Selective introduction of fluorine and subsequent transformations are key synthetic challenges.

Purpose of the Study:

• To develop a copper-catalyzed method for site-selective benzylic C-H fluorination.
• To demonstrate the utility of the generated benzyl fluorides in subsequent coupling reactions.
• To establish a streamlined approach for accessing diverse functionalized benzyl derivatives.

Main Methods:

• Copper-catalyzed C-H fluorination using N-fluorobenzenesulfonimide (NFSI).
• Nucleophilic substitution of the in situ generated benzyl fluorides.
• Subsequent C-O, C-N, and C-C coupling reactions facilitated by hydrogen-bond donors or Lewis acids.

Main Results:

• Achieved site-selective fluorination at benzylic C-H bonds.
• Demonstrated successful substitution of the benzyl fluoride with various nucleophiles (e.g., alcohols, amines, carbon nucleophiles).
• Enabled one-pot sequential fluorination-coupling reactions without isolation of intermediates.

Conclusions:

• The developed Cu-catalyzed C-H fluorination provides an efficient route to benzyl fluorides.
• The generated benzyl fluorides are versatile electrophiles for diverse coupling reactions.
• This methodology offers a powerful tool for the synthesis of functionalized organic molecules.