The higher reactivity of the C4-H bond as compared to the C5-H bond of 1,2,3-trifluorobenzene in palladium-catalyzed direct arylation allows the selective synthesis of 4-aryl-1,2,3-trifluorobenzenes in moderate to high yields. In most cases, phosphine-free Pd(OAc)₂ catalyst and inexpensive KOAc base were employed. Then, from these 4-aryl-1,2,3-trifluorobenzenes, the palladium-catalyzed C–H bond functionalization of the C6-position allows the synthesis of the corresponding 4,6-diarylated 1,2,3-trifluorobenzenes. We also applied these reaction conditions to the regioselective direct C3-arylation of 1,2,4-trifluorobenzene.

中文翻译：

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1,2,3-和1,2,4-三氟苯在钯催化的直接芳基化反应中的反应性

在钯催化的直接芳基化反应中，与1,2,3-三氟苯的C5-H键相比，C4-H键具有更高的反应活性，可以选择性合成中度至高分子量的4-芳基-1,2,3-三氟苯高产。在大多数情况下，使用无膦的Pd（OAc）₂催化剂和廉价的KOAc碱。然后，从这些4-芳基-1,2,3-三氟苯中，钯催化的C6-位的C–H键官能化可以合成相应的4,6-二芳基化的1,2,3-三氟苯。我们还将这些反应条件应用于1,2,4-三氟苯的区域选择性直接C3-芳基化。