Cross-coupling reaction on N-(3,5-dibromo-2-pyridyl)piperazines: regioselective synthesis of 3,5-disubstituted pyridylpiperazines

Unsymmetrical 3,5-disubstituted pyridylpiperazines were prepared from tribromopyridine in three coupling reactions. Key to the success of the syntheses is the palladium-catalyzed regioselective cross-coupling reaction in the 3-position of N-(3,5-dibromo-2-pyridyl)piperazines.