Synthesis of Acyl Fluorides via DAST-Mediated Fluorinative C-C Bond Cleavage of Activated Ketones.

A new protocol for preparation of acyl fluorides was developed by recognizing activated ketones as starting materials. The method provides a different scope compared with previously reported methods that employ carboxylic acids as substrates. A working hypothesis of pull-and-push-driven fluorinative C-C bond cleavage was successfully demonstrated by the simple addition of diethylaminosulfur trifluoride (DAST) derivatives to α-oximinoketones. The designed reaction system led to a highly efficient and chemoselective reaction. The wide availability of the ketones allowed for a range of synthetically useful aryloyl and aliphatic acyl fluorides including those containing chiral skeletons. The method is mild, fast, scalable, and potentially one-pot operative.