Mono-β-diketonate compounds have been fleetingly observed in base metal catalyzed reactions, which are of current interest as alternatives to precious metal catalyzed reactions. Their isolation has been challenging due to synthetic and structural limitations of acac-type ligands, leading to the development of a related NacNac ligand platform. Herein we report the synthesis of a β-diketone capable of kinetically stabilizing relevant catalytic intermediates. Their efficient synthesis requires isolable acyl triflate and lithium enolate reactants. Further, the syntheses of several transmetalation salts are reported and used in transmetalation reactions with a series of late, first-row transition metal compounds (Fe^II, Co^II, Ni^II, Cu^I, Cu^II) of interest in base metal catalysis. In all, a dozen single-crystal XRD structures are reported, among other methods of characterization (i.e., IR, UV–vis, NMR, HRMS). The majority of the compounds present as mono-β-diketonate small-molecule bridged dimers. They serve as effective precatalysts and are accurately modeled by DFT calculations, validating the use of computational methods for determining structures and mechanisms. Their reactivity with various small molecules and solvents is also described. The utility of bis(2,6-dimesitylbenzoyl)methane (L) as a supporting ancillary ligand and a tool for further rational development of this class of ligands is discussed.

中文翻译：

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第一过渡系列的单β二酮酸盐金属配合物


在贱金属催化反应中短暂观察到单β-二酮酸盐化合物，这些反应目前作为贵金属催化反应的替代品而受到关注。由于 acac 型配体的合成和结构限制，它们的分离一直具有挑战性，因此开发了相关的 NacNac 配体平台。在此，我们报道了能够动力学稳定相关催化中间体的 β-二酮的合成。它们的高效合成需要可分离的酰基三氟甲磺酸酯和烯醇化锂反应物。此外，在贱金属催化中，报道了几种金属转移盐的合成，并将其用于与一系列感兴趣的后期第一行过渡金属化合物 （Fe^II， Co^II， Ni^II， Cu， Cu^II） 进行金属转移反应。总共报道了十几种单晶 XRD 结构，以及其他表征方法（即 IR、UV-Vis、NMR、HRMS）。大多数化合物以单β-二酮酸小分子桥式二聚体的形式存在。它们用作有效的预催化剂，并通过 DFT 计算进行准确建模，验证了计算方法在确定结构和机制方面的使用。还描述了它们与各种小分子和溶剂的反应性。讨论了双（2,6-二美硅基苯甲酰基）甲烷 （L） 作为支持辅助配体和进一步合理开发此类配体的工具的效用。