Diborylfluoromethane as C1F1 Synthon for the Synthesis of α-Fluoroketones.

The selective α-monofluorination of ketones is a significant synthetic challenge. In this study, we introduce a base-promoted coupling reaction that utilizes carboxylic acid esters and diborylfluoromethane, which serves as synthetic equivalent of a monofluorinated C1 (C1F1) synthon. This reaction provides an efficient and convergent synthetic strategy for making α-fluoroketones. It generates a boron-enolate equivalent that can be subsequently trapped with water and other electrophiles, including alkyl halides and fluorinating agents.