Fig. 1: Proposed catalytic cycle for the β-C(sp3)–H fluorination of free carboxylic acids.
From: Pd-catalysed direct β-C(sp3)–H fluorination of aliphatic carboxylic acids
A proposed catalytic cycle consisting of a C–H activation giving intermediate 1, an OA to give intermediate 2, a ligand exchange giving intermediate 3 and a RE giving the product and regenerating the catalyst is shown, as well as a potential alternate mechanism with an electrophilic fluorinating agent going directly from Int-1 to Int-3 (ref. 23). Challenges associated with the target transformation are shown, and the concept of oxidant design to address these challenges is introduced. Int, intermediate; LG, leaving group; OX/OY, fragments of the designed oxidant.
