Tandem Blaise/Palladium-Catalyzed Ullmann Coupling for the One-Pot Synthesis of Enamino Ester-Functionalized Biaryls from Nitriles

A novel Pd-catalyzed Ullmann-type
homocoupling reaction of the
Blaise reaction intermediate generated by the reaction of 2-bromo
arylnitriles and a Reformatsky reagent has been developed for one-pot
synthesis of enamino ester-functionalized biaryls 2 in
good yields. The 2,2′-substituted enamine moieties of the coupling
products could be cyclized under acidic conditions through the conjugate
addition/deamination cascade to afford the seven-membered N-heterocyclics 3 with biaryl backbone in excellent
yields.