Gold-Catalyzed Synthesis of α-Fluoro Acetals and α-Fluoro Ketones from Alkynes

A new method to synthesize alpha-fluoro acetals and alpha-fluoro ketones is presented here. In the presence of alcohols and Selectfluor, catalytic amounts of gold selectively transformed alkynes into the corresponding fluorinated acetals or ketones depending on the reaction conditions. This protocol has been applied to both terminal and internal alkynes showing a high degree of chemo-and regioselectivity. The reaction mechanism seems to proceed via two co-existing pathways, since at least partially, the formation of the C(sp(3))-F bond in the final products occurs at the metal center.