Testing different palladium sources (e.g. Pd(dppf)Cl2•DCM) and different solvents (e.g. dichloroethane) also gave very low yields. Changing the base to sodium carbonate decreased the yield (entry 6), while using cesium carbonate in the solvent system gave the best result with 45% isolated yield (entry 7) of the desired coupled product 5. The remaining mass balance was attributed to the formation of monocoupled product 6 (26% isolated yield) and a mixture of starting material 4 and debrominated starting material. With sufficiently optimized conditions in hand, the Suzuki coupling was scaled up from the optimization scale of 23 µmol to a 0.7 mmol scale without significant impact on the yield (43% isolated yield).