Hypervalent Iodine-Catalyzed Fluorination of Diene-Containing Compounds: A Computational Study

Area of Science:

• Organic Chemistry
• Catalysis
• Fluorination Chemistry

Background:

• Incorporating fluorine enhances material properties, but C-F bond formation is challenging.
• Hypervalent iodine catalysis for alkene fluorination is known, yet mechanisms remain underexplored.

Purpose of the Study:

• To elucidate the reaction mechanism of hypervalent iodine-catalyzed 1,4-difluorination of dienes.
• To understand the role of catalyst activation, intermediate formation, and fluorination steps.

Main Methods:

• Computational studies were employed to investigate the reaction pathway.
• Analysis of catalyst activation via halogen bonding and intermediate stabilization through hydrogen bonding.

Main Results:

• Hypervalent iodine activates dienes via halogen bonds, forming [F-H∙∙∙F]⁻ intermediates via hydrogen bonding with HF.
• The [F-H∙∙∙F]⁻ intermediate attacks the diene regioselectively, followed by nucleophilic substitution of the catalyst.
• Stabilization of transition states is favored by HF interactions, with two HF molecules being optimal.

Conclusions:

• A novel mechanism for hypervalent iodine-catalyzed diene difluorination is proposed.
• The study highlights the importance of halogen and hydrogen bonding in facilitating C-F bond formation.
• Computational insights provide a foundation for designing more efficient fluorination strategies.