Regioselective Pd(0)-Catalyzed Hiyama Cross-Coupling Reactions at Dihalo-Substituted Heterocycles

The regioselectivity of the Hiyama cross-coupling reaction at various dihalo-substituted heterocycles has been Studied. Methyl 2,3-dibromo-5-furancarboxylate and n-octyltrifluorosilane were employed to find optimum reaction conditions [CsF; Pd(2)dba(3)/P(2-furyl)(3) as catalyst, 80-150 degrees C in toluene or benzene] for the desired transformation. Subsequent experiments with the title compounds and with different primary alkyltrifluorosilanes illustrate the generality of this regiochemical process.