Institute of Organic Chemistry, Universität Regensburg, Universitätstrasse 31, 93053, Regensburg, Germany.
Angew Chem Int Ed Engl. 2021 Dec 1;60(49):25832-25838. doi: 10.1002/anie.202106881. Epub 2021 Nov 3.
The weak noncovalent interactions and flexibility of ligands play a key role in enantioselective metal-catalyzed reactions. In transition metal complexes and their catalytic applications, the experimental assessment and the design of key interactions is as difficult as the prediction of the enantioselectivities, especially for flexible, privileged ligands such as chiral phosphoramidites. Therefore, the interligand interactions in cis-Pd L Cl phosphoramidite complexes were investigated by NMR spectroscopy and computations. We were able to induce a strong conformational preference by breaking the symmetry of the C -symmetric side chain of one of the ligands, and shift the equilibrium between hetero- and homocomplexes towards heterocomplexes because of interligand interactions in the cis-complexes. The modulation of aryl substituents was exploited, along with the solvent effect. The combined CH-π and π-π interactions reveal design patterns for binding and folding of chiral ligands and catalysts.
弱的非共价相互作用和配体的柔韧性在对映选择性金属催化反应中起着关键作用。在过渡金属配合物及其催化应用中，关键相互作用的实验评估和设计与对映选择性的预测一样困难，特别是对于柔性、手性膦酰胺配体等特权配体。因此，通过 NMR 光谱和计算研究了顺式-PdLCl 膦酰胺配体配合物中的配体间相互作用。我们能够通过打破一个配体的 C 对称侧链的对称性来诱导强烈的构象偏好，并由于顺式配合物中的配体间相互作用，使杂-同和同-同复合物之间的平衡向杂复合物转移。利用了芳基取代基的调制以及溶剂效应。CH-π 和 π-π 相互作用揭示了手性配体和催化剂的结合和折叠的设计模式。
