Acid-Enabled Palladium-Catalyzed β-C(sp)-H Functionalization of Weinreb Amides.

Pd-catalyzed modification of C-H bonds via chelation with weakly coordinating groups normally requires a transient directing group or presynthesized nitrogen-based strong coordinating ligands. Herein, we report Pd(II)-catalyzed C(sp)-H arylation and alkenylation of Weinreb amides. A commercially available, inexpensive sulfonic acid was employed to enhance the coordination of the catalyst with weak-coordinating substrates by increasing the electrophilicity of in situ formed palladium catalysts.