Palladium-catalyzed aerobic oxidation reactions have been the focus of industrial application and extensive research efforts for nearly 60 years. A significant transition occurred in this field approximately 20 years ago, with the introduction of catalysts supported by ancillary ligands. The ligands play crucial roles in the reactions, including promotion of direct oxidation of palladium(0) by O₂, bypassing the typical requirement for Cu salts or related redox cocatalysts to facilitate oxidation of the reduced Pd catalyst; facilitation of key bond-breaking and bond-forming steps during substrate oxidation; and modulation of chemo-, regio-, or stereoselectivity of a reaction. The use of ligands has contributed to significant expansion of the scope of accessible aerobic oxidation reactions. Increased understanding of the role of ancillary ligands should promote the development of new synthetic transformations, enable improved control over the reaction selectivity, and improve catalyst activity and stability. This review surveys the different ligands that have been used to support palladium-catalyzed aerobic oxidation reactions and, where possible, describes mechanistic insights into the role played by the ancillary ligand.

中文翻译：

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配体促进的钯催化的好氧氧化反应

钯催化的好氧氧化反应一直是工业应用和广泛研究工作的重点，已有近60年的历史。大约20年前，伴随着辅助配体负载的催化剂的引入，该领域发生了重大转变。配体在反应中起关键作用，包括促进O ₂对钯（0）的直接氧化。绕过对铜盐或相关氧化还原助催化剂的典型要求，以促进还原的Pd催化剂的氧化；促进基片氧化过程中关键的键断裂和键形成步骤；反应的化学选择性，区域选择性或立体选择性的调节。配体的使用大大促进了可达到的需氧氧化反应范围的扩大。对辅助配体作用的进一步了解将促进新合成转化的发展，使对反应选择性的控制得到改善，并提高催化剂的活性和稳定性。这篇综述调查了已经用于支持钯催化的需氧氧化反应的不同配体，并在可能的情况下，描述了对辅助配体所发挥作用的机理性见解。