Regioselective Chlorination of Quinoline N-Oxides and Isoquinoline N-Oxides Using PPh₃/Cl₃CCN

A novel method for the regioselective C2-chlorination of heterocyclic N-oxides has been developed. PPh₃/Cl₃CCN were used as chlorinating reagents and the desired N-heterocyclic chlorides were obtained smoothly in satisfactory yields. The reactions proceeded in a highly efficient and selective manner across a broad range of substrates demonstrating excellent functional group tolerance. In addition, this chlorination reaction can be used for the modification of N-heterocyclic scaffolds of appealing ligands and pharmaceuticals.