Acyl Amidines by Pd-Catalyzed Aminocarbonylation: One-Pot Cyclizations and (11)C Labeling

[Image: see text] A protocol for the carbonylative synthesis of acyl amidines from aryl halides, amidines, and carbon monoxide catalyzed by Pd(0) is reported herein. Notably, carbon monoxide is generated ex situ from a solid CO source, and several productive palladium ligands were identified with complementary benefits and substrate scope. Furthermore, sequential one-pot, two-step protocols for the synthesis of 1,2,4-triazoles and 1,2,4-oxadiazoles via acyl amidine intermediates are reported. In addition, this approach was extended to isotopic labeling using [(11)C]carbon monoxide to allow, for the first time, synthesis of (11)C-labeled acyl amidines as well as a (11)C-labeled 1,2,4-oxadiazole.