Halide-Accelerated Acyl Fluoride Formation Using Sulfuryl Fluoride

Herein, we report a new one-pot sequential method for SO2F2-mediated nucleophilic acyl substitution reactions starting from carboxylic acids. A mechanistic study revealed that SO2F2-mediated acid activation proceeds via the anhydride, which is then converted to the corresponding acyl fluoride. Tetrabutylammonium chloride or bromide accelerate the formation of acyl fluoride. Optimized halide-accelerated conditions were used to synthesize acyl fluorides in 30–80% yields, and esters, amides, and thioesters in 72–96% yields without reoptimization for each nucleophile.