Synthesis of Biquinolines via a Pd‐Catalyzed Borylation Reaction

Abstract Synthesis of biquinolines starting from easily available haloquinolines via a Pd‐catalyzed borylation reaction in the presence of inexpensive bis(pinacolato)diboron is described. The reaction involves Pd(dppf)Cl 2 ⋅ CH 2 Cl 2 ‐catalyzed cross‐coupling of haloquinolines with bis(pinacolato)diboron to afford in situ generated heteroarylboronates. The intermediate heteroarylboronates immediately undergoes homocoupling to afford biquinolines in good to excellent yields in short reaction time. The scope of the reaction was demonstrated by its successful extension to structurally related N ‐heterocycles.