Fluorohydrin Synthesis via Formal C-H Fluorination of Cyclic Alcohols

Area of Science:

• Organic Chemistry
• Fluorination Chemistry

Background:

• The installation of carbon-fluorine (C-F) bonds is crucial for pharmaceuticals, agrochemicals, and materials.
• Direct C-H fluorination offers an efficient route to C-F bond formation, replacing less desirable C-H bonds.

Purpose of the Study:

• To develop a novel method for direct C-H fluorination of cyclic alcohols.
• To synthesize cyclic fluorohydrins from readily available cyclic alcohols.

Main Methods:

• Utilized Selectfluor as the fluorinating agent.
• Applied the method to 5-, 6-, 7-, and 8-membered cyclic alcohols.
• Conducted mechanistic studies to elucidate the reaction pathway.

Main Results:

• Successfully generated cyclic fluorohydrins via direct C-H fluorination.
• Demonstrated the method's applicability across various ring sizes of cyclic alcohols.
• Identified an ionic elimination-hydroxyfluorination cascade mechanism involving an alkene intermediate.

Conclusions:

• The developed method provides a direct and efficient route to cyclic fluorohydrins.
• The reaction proceeds through a proposed ionic elimination-hydroxyfluorination cascade.
• This work expands synthetic capabilities for incorporating fluorine into cyclic structures.