Extended Data Figure 2: The effect of potassium and fluoride salts on the selectivity of the multimetal-catalysed cross-Ullmann reaction.
From: Multimetallic catalysed cross-coupling of aryl bromides with aryl triflates
The presence of potassium fluoride (KF) in cross-couplings has been demonstrated to improve the product yield and rate of reactions while minimizing the formation of dimeric products. This ‘KF effect’ can be attributed to a variety of different factors, including the formation of ‘ate’ complexes, the removal of a halide from a metal complex, or the formation of a fluoride-bridged complex, which could facilitate an oxidative addition or transmetallation step23,25. a, b, To investigate whether KF could be beneficial for the nickel and palladium multimetallic system, we included various amounts of this additive under standard reaction conditions. The resulting selectivity and rate data are shown. c, d, Once the advantageous role of KF was confirmed, other potassium and fluoride salts were tested. The resulting selectivity and rate data are shown. The presence of potassium resulted in faster reaction rates, while the presence of fluoride reduced the amount of bianisole and biphenyl byproducts, improving the yield of cross-product. (Reactions without additives took 32 h to complete.)
