A novel monofluoroallylsulfonium salt (MFAS) is synthesized from the inexpensive industrial chemical 3,3,3-trifluoropropene in three steps with high efficiency. This reagent reacts readily with a series of alkylzinc reagents under copper catalysis to yield allylic monofluorides with high regioselectivity and excellent yields.

A bench-stable and scalable monofluoroallylsulfonium salt (MFAS) has been developed for highly regioselective mono-fluoroallylation. This reagent is synthesized from the inexpensive industrial chemical 3,3,3-trifluoropropene in three steps with high efficiency. The reaction of alkylzinc reagents with MFAS proceeds smoothly under copper catalysis, yielding allylic monofluorides with excellent regioselectivity and high reaction efficiency. The synthetic utility of this reagent is demonstrated by transformations of the monofluoroallylated products.