Direct β‐ and γ‐C(sp(3))−H Alkynylation of Free Carboxylic Acids

In this study we report the identification of a novel class of ligands for palladium‐catalyzed C(sp(3))−H activation that enables the direct alkynylation of free carboxylic acid substrates. In contrast to previous synthetic methods, no introduction/removal of an exogenous directing group is required. A broad scope of acids including both α‐quaternary and challenging α‐non‐quaternary can be used as substrates. Additionally, the alkynylation in the distal γ‐position is reported. Finally, this study encompasses preliminary findings on an enantioselective variant of the title transformation as well as synthetic applications of the products obtained.