Noncovalent CH–π and π–π Interactions in Phosphoramidite Palladium(II) Complexes with Strong Conformational Preference

Žabka, Matej; Naviri, Lavakumar; Gschwind, Ruth M.

doi:10.1002/anie.202106881

Cited by 15 publications

(18 citation statements)

References 78 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Int. Ed.2021602538225838 . This study demonstrates how London dispersion interactions can be detected and quantified in transition metal complexes and shows that rigid structures lead to strong stabilization effects by dispersion. Tilting the Balance: London Dispersion Systematically Enhances Enantioselectivities in Brønsted Acid Catalyzed Transfer Hydrogenation of IminesGramüllerJ.FrantaM.GschwindR.…”

Section: Key Referencesmentioning

confidence: 78%

Section: Key Referencesmentioning

confidence: 99%

“… a The cis -Pd( X )( F )Cl 2 : cis -Pd( F ) 2 Cl 2 : cis -Pd( X ) 2 Cl 2 ratios are given and were determined by integration in the 31 P { 1 H} NMR spectra in CD 2 Cl 2 at 300 K. The interligand interaction areas were revealed by combining NMR structural analysis (NOESY) and density functional theory (DFT) calculations. b ΔΔG was calculated as the difference between ΔG of the matched and mismatched equilibrium, assuming that the concentration of cis -Pd( X ) 2 Cl 2 was equal to that of cis -Pd( F ) 2 Cl 2 , irrespective of the other X homocomplexes present. Adapted with permission from ref . Copyright 2021 John Wiley & Sons. …”

Section: London Dispersion In Transition Metal Catalysismentioning

confidence: 99%

“…In the field of asymmetric transition metal catalysis, we used palladium complexes with privileged phosphoramidite ligands as a supramolecular balance to quantify the LD interactions in transition metal complexes (see Figure 1, top right). 1 Using ligand variations and NMR spectroscopy for conformational analysis, a correlation was observed between the conformational stability and the high thermodynamic preference of heterodimer formation. This demonstrated that LD can unfold its full potential only in cases where entropic contributions are minimized.…”

Section: Introductionmentioning

confidence: 99%

“…In this Account, we summarize the key findings of our investigations of the role of LD in catalytic systems. In the field of asymmetric transition metal catalysis, we used palladium complexes with privileged phosphoramidite ligands as a supramolecular balance to quantify the LD interactions in transition metal complexes (see Figure , top right) . Using ligand variations and NMR spectroscopy for conformational analysis, a correlation was observed between the conformational stability and the high thermodynamic preference of heterodimer formation.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

An NMR Spectroscopy View on London Dispersion in Catalysis: Detection, Quantification, and Application in Ion Pair and Transition Metal Catalysis

Gramüller,

Gschwind

2023

Acc. Chem. Res.

Self Cite

View full text Add to dashboard Cite

Metrics & MoreArticle Recommendations CONSPECTUS:The energetic contribution of London dispersion (LD) can cover a broad range from very few to hundreds of kJ mol −1 for extended interaction interfaces due to its pairwise additivity. However, for a designed and successful application of LD in chemical catalysis, there are still many obstacles and questions that remain. In principle, LD can be regarded as the attractive part of the van der Waals potential. Thus, considering the whole van der Waals potential, including the repulsive part (steric repulsion), the ideal solution to the problem in catalysis would be to design compatible interaction interfaces at exactly the correct distance. In the case of a self-assembled, flexible structure arrangement, entropic contributions and solvent interactions might be detrimental. In the case of a rigid catalyst pocket, steric hindrance might not allow for large substituents that are usually applied as dispersion energy donors (DEDs). For a working catalytic system, the following question arises: how is it possible to dissect the complex interaction interfaces in terms of energetic contributions? Usually, the energetic contribution of LD to catalysis is addressed by using calculations. However, adequately computing the correct energetic contributions can be extremely challenging for a vast conformational space with all kinds of intermolecular interactions. Thus, experimental data are essential for comparison or benchmarking. Therefore, in this Account, we describe our quest for detailed experimental data obtained via NMR spectroscopy to experimentally dissect and quantify LD in catalytic systems. In addition, we address the question of whether bulky substituents used as DEDs can be used in confined catalytic pockets. With the example of Pd phosphoramidite complexes, we show how it is possible to experimentally dissect and quantify the contribution of individual interaction areas in complicated transition metal complexes. Furthermore, a correlation between conformational rigidity and heterodimer preference clearly reveals that LD can only unfold its full potential in cases where entropic contributions are minimized. This finding can also explain the small contribution of LD in flexible and solventexposed molecular balances. In the field of Brønsted acid catalysis, we demonstrated that LD has a strong influence on the structures, stability, and populations of confined catalytic intermediates. LD is key for populating higher aggregates such as dimers. In addition, offsets between the experimental and computational results were observed and attributed to solvent−solute dispersion interactions. We studied the delicate interplay of attractive and repulsive interactions by adding bulky DED substituents onto a substrate, which can function as a molecular balance system. Intriguingly, the effect of LD on the free substrate was straightforwardly transferred onto the highly confined intermediates. Furthermore, this effect could even be read out in the enantioselectivities of the underlyi...

show abstract

Section: Key Referencesmentioning

confidence: 78%

Section: Key Referencesmentioning

confidence: 99%

Section: London Dispersion In Transition Metal Catalysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

An NMR Spectroscopy View on London Dispersion in Catalysis: Detection, Quantification, and Application in Ion Pair and Transition Metal Catalysis

Gramüller,

Gschwind

2023

Acc. Chem. Res.

Self Cite

View full text Add to dashboard Cite

show abstract

Benzo‐fused Nitrogen Heterocycles by Asymmetric Ring Expansion and Stereochemically Retentive Re‐contraction of Cyclic Ureas

Mallick,

Žabka,

Clayden

2024

Angewandte Chemie

Self Cite

View full text Add to dashboard Cite

Benzo‐fused nitrogen heterocycles are common features of bioactive molecules, and the enantioselective synthesis of their substituted analogues is an important goal. In this paper we demonstrate a practical and mechanistically intriguing approach to the enantioselective synthesis of 1‐arylbenzazepines and their analogues. The reaction sequence starts with an asymmetric migratory ring expansion of indoline, tetrahydroquinoline, or tetrahydrobenzazepine ureas on treatment with a chiral lithium amide base. Treatment of the ring‐expanded ureas with acid triggers a two‐atom ring contraction – an ‘azatropic shift’ in which one urea nitrogen displaces the other – with almost complete retention of stereochemistry. Aminolysis of the urea products provides enantioenriched 1‐aryl‐tetrahydrobenzazepine derivatives and their congeners, including an analogue of an intermediate in the synthesis of the drug solifenacin. Deuteration, in situ IR, and DFT studies provide evidence for the mechanisms of the reaction steps.

show abstract

Asymmetric Pd/Organoboron‐Catalyzed Site‐Selective Carbohydrate Functionalization with Alkoxyallenes Involving Noncovalent Stereocontrol

Guo,

Kirchhoff,

Strohmann

et al. 2024

Angewandte Chemie

View full text Add to dashboard Cite

Herein, we demonstrate the robustness of a synergistic chiral Pd/organoboron system in tackling a challenging suite of site‐, regio‐, enantio‐ and diastereoselectivity issues across a considerable palette of biologically relevant carbohydrate polyols, when prochiral alkoxyallenes were employed as electrophiles. In view of the burgeoning role of noncovalent interactions (NCIs) in stereoselective carbohydrate synthesis, our mechanistic experiments and DFT modeling of the reaction path unexpectedly revealed that NCIs such as hydrogen bonding and CH‐π interactions between the resting states of the Pd‐π‐allyl complex and the borinate saccharide are critically involved in the stereoselectivity control. Our strategy thus illuminates the untapped potential of harnessing NCIs in the context of transition metal catalysis to tackle stereoselectivity challenges in carbohydrate functionalization.

show abstract

Noncovalent CH–π and π–π Interactions in Phosphoramidite Palladium(II) Complexes with Strong Conformational Preference

Cited by 15 publications

References 78 publications

An NMR Spectroscopy View on London Dispersion in Catalysis: Detection, Quantification, and Application in Ion Pair and Transition Metal Catalysis

An NMR Spectroscopy View on London Dispersion in Catalysis: Detection, Quantification, and Application in Ion Pair and Transition Metal Catalysis

Benzo‐fused Nitrogen Heterocycles by Asymmetric Ring Expansion and Stereochemically Retentive Re‐contraction of Cyclic Ureas

Asymmetric Pd/Organoboron‐Catalyzed Site‐Selective Carbohydrate Functionalization with Alkoxyallenes Involving Noncovalent Stereocontrol

Contact Info

Product

Resources

About