A Reagent for the One-Step Preparation of Potassium Acyltrifluoroborates (KATs) from Aryl- and Heteroarylhalides

Potassium acyltrifluoroborates (KATs) are fascinating functional groups whose further exploration is limited by poor synthetic access. Documented herein is the design and synthesis of a new reagent for their one-step preparation from aryl- and heteroarylhalides. The reagent is a stable, soluble zwitterion prepared by S-alkylation of a novel thioformamide trifluoroboronate. The KATs are prepared by adding one equivalent of nBuLi to a mixture of the aryl halide and the reagent at similar to 78 degrees C. This protocol is suitable for the preparation of KATs containing pyridines, esters, nitro groups, and halides.