Palladium-Catalyzed Direct Ethynylation of C(sp3)-H Bonds in Aliphatic Carboxylic Acid Derivatives

The first catalytic alkynylation of unactivated C(sp(3))-H bonds has been accomplished. The method allows for the straightforward introduction of an ethynyl group into aliphatic acid derivatives under palladium catalysis. This new reaction can be applied to the rapid elaboration of complex aliphatic acids, for example, via azide/alkyne cycloaddition.