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J. Org. Chem. 2019, 84, 4680−4694. DOI:10.1021/acs.joc.8b02269 ◆ KOAc has low solubility in toluene, even at elevated temperatures, and the crystallinity of as-received KOAc likely results in slow dissolution kinetics. ◆ Given that grinding a hygroscopic solid would be undesirable on a larger scale, we sought to identify an alternative base that would alleviate mass-transfer issues. ◆ The proposed mechanisms for both the Miyaura borylation and direct arylation proceed through Pd(carboxylate) intermediates, and it has been shown that pivalate ligands have a pronounced positive effect on direct arylation chemistry. ◆ We therefore investigated both KOPiv as bases, either as the discrete carboxylate salts or generated in situ using amixture of pivalic acid and K2CO3. ◆ While these reaction end point results are very similar to those obtained with KOAc, use of pivalate has a striking effect on reaction rate ◆ In contrast to KOAc and KOPiv, K2CO3 is readily available in a numbe
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