Enolizable β-Fluoroenones: Synthesis and Asymmetric 1,2-Reduction

Area of Science:

• Organic Chemistry
• Fluorination Chemistry

Background:

• Enolizable ynones are versatile synthetic precursors.
• Hydrofluorination reactions are crucial for introducing fluorine into organic molecules.
• Beta-fluoroenones are valuable intermediates with unique reactivity.

Purpose of the Study:

• To develop an efficient method for the hydrofluorination of enolizable ynones.
• To control selectivity and suppress side product formation.
• To explore the synthetic utility of the obtained beta-fluoroenones.

Main Methods:

• Hydrofluorination of enolizable ynones using silver fluoride (AgF) in t-BuOH/DMF.
• Use of 2,2'-biphenol as an additive to suppress furan formation.
• Asymmetric 1,2-reduction of beta-fluoroenones using pinacolborane and a Ni(0) catalyst.

Main Results:

• Efficient synthesis of beta-fluoroenones with good Z-selectivity.
• Suppression of furan formation using 2,2'-biphenol.
• Tolerance of a variety of functional groups.
• Demonstration of asymmetric reduction to 3-fluoroallylic alcohols.

Conclusions:

• The reported hydrofluorination method provides a reliable route to Z-beta-fluoroenones.
• The use of 2,2'-biphenol is effective in controlling side reactions.
• The resulting beta-fluoroenones are stable under reaction conditions and amenable to further functionalization, including asymmetric reduction.