Patrick Müller


Last Name

Müller

First Name

Patrick

ORCID

0000-0001-7253-7198

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2022 - 20257
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Publications 1 - 7 of 7
  • Direct Synthesis of Unprotected Indolines Through Intramolecular sp³ C−H Amination Using Nitroarenes as Aryl Nitrene Precursors
    Item type: Journal Article
    Sirvinskaite, Giedre; Nardo, Celine S.; Müller, Patrick; et al. (2023)
    Chemistry - A European Journal
    Given the prevalence of molecules containing nitro groups in organic synthesis, innovative methods to expand the reactivity of this functional group are of interest in both industrial and academic settings. In this report, a metal-free intramolecular benzylic sp³ C−H amination is disclosed using aryl nitro compounds as aryl nitrene precursors. Organosilicon reagent N,N’-bis(trimethylsilyl)-4,4’-bipyridinylidene (Si-DHBP) served as an efficient reductant in the transformation, enabling the in situ generation of aryl nitrene species for the direct, metal-free synthesis of unprotected 2-arylindolines from the corresponding nitroarene compounds.
  • Mechanistic Investigation of the Nickel-Catalyzed Metathesis between Aryl Thioethers and Aryl Nitriles
    Item type: Journal Article
    Boehm, Philip; Müller, Patrick; Finkelstein Dobratz, Patrick; et al. (2022)
    Journal of the American Chemical Society
    Functional group metathesis is an emerging field in organic chemistry with promising synthetic applications. However, no complete mechanistic studies of these reactions have been reported to date, particularly regarding the nature of the key functional group transfer mechanism. Unraveling the mechanism of these transformations would not only allow for their further improvement but would also lead to the design of novel reactions. Herein, we describe our detailed mechanistic studies of the nickel-catalyzed functional group metathesis reaction between aryl methyl sulfides and aryl nitriles, combining experimental and computational results. These studies did not support a mechanism proceeding through reversible migratory insertion of the nitrile into a Ni–Ar bond and provided strong support for an alternative mechanism involving a key transmetalation step between two independently generated oxidative addition complexes. Extensive kinetic analysis, including rate law determination and Eyring analysis, indicated the oxidative addition complex of aryl nitrile as the resting state of the catalytic reaction. Depending on the concentration of aryl methyl sulfide, either the reductive elimination of aryl nitrile or the oxidative addition into the C(sp2)–S bond of aryl methyl sulfide is the turnover-limiting step of the reaction. NMR studies, including an unusual 31P–2H HMBC experiment using deuterium-labeled complexes, unambiguously demonstrated that the sulfide and cyanide groups exchange during the transmetalation step, rather than the two aryl moieties. In addition, Eyring and Hammett analyses of the transmetalation between two Ni(II) complexes revealed that this central step proceeds via an associative mechanism. Organometallic studies involving the synthesis, isolation, and characterization of all putative intermediates and possible deactivation complexes have further shed light on the reaction mechanism, including the identification of a key deactivation pathway, which has led to an improved catalytic protocol.
  • Nickel(I)-Phenolate Complexes: The Key to Well-Defined Ni(I) Species
    Item type: Journal Article
    Müller, Patrick; Finkelstein Dobratz, Patrick; Trapp, Nils; et al. (2023)
    Inorganic Chemistry
    Phosphine-stabilized monovalent nickel complexes play an important role in catalysis, either as catalytically active species or as decomposition products. Most routes to access these complexes are highly ligand specific or rely on strong reducing agents. Our group recently disclosed a path to access nickel(I)-phenolate complexes from bis(1,5-cyclooctadiene)nickel(0) (Ni(cod)(2)). Herein, we demonstrate this protocol's broad applicability by ligating a wide range of mono- and bidentate phosphine ligands. We further show the versatility of the phenolate fragment as a precursor to nickel(I)-alkyl or aryl species, which are relevant to Ni catalysis or synthetically useful nickel(I)-chloride and hydride complexes. We also demonstrate that the chloride complex can be synthesized in a one-pot procedure starting from Ni(cod)(2) in good yield, making this protocol a valuable alternative to current procedures. Single-crystal X-ray diffraction, IR, and EPR (or NMR) spectroscopy were employed to characterize all of the synthesized nickel complexes.
  • Structural Evidence for Aromatic Heterocycle N-O Bond Activation via Oxidative Addition
    Item type: Journal Article
    Bogdos, Michael K.; Müller, Patrick; Morandi, Bill (2023)
    Organometallics
    Many methods report the scission of N-O bonds of aromatic heterocycles and their subsequent functionalization. Oxidative addition is one of the presumed pathways through which aromatic N-O bond activation with transition metals is achieved. We report the first well-defined pathway of (benz)isoxazole's aromatic N-O bond activation through oxidative addition. We also provide control experiments, which show that aromatic N-O bonds may be broken by strong inorganic reductants. These results highlight that N-O bonds are susceptible to both reduction and oxidative addition, which has important implications for catalysis. Exploring the reactivity of one of these complexes toward a series of electrophiles leads to the discovery of a Staudinger-type beta-lactam synthesis upon the reaction with a ketene. Finally, we demonstrate that the choice of different metal/ligand combinations allows for selective oxidative addition into either C-I bonds or N-O bonds in the presence of the other.
  • Intermolecular Synthesis of Coumarins from Acid Chlorides and Unactivated Alkynes through Palladium Catalysis
    Item type: Journal Article
    Schmitt, Hendrik L.; Staeck, Niels; Müller, Patrick; et al. (2025)
    Organic Letters
    We describe a modular synthetic pathway to directly obtain coumarins from acid chlorides and alkynes. A Pd catalyst employing 3,5-CF₃-Ph-DPEPhos as the ancillary ligand was found to unlock this reactivity, enabling the conversion of a variety of 2-methoxy benzoyl chlorides and alkynes to the corresponding coumarins. Besides acid chlorides, the in situ generation of this reactive species from the corresponding acid was also possible. Finally, control experiments and preliminary kinetic analyses were performed to understand the role of the catalyst.
  • Metal Electronics Mediate Steric and Coordination Number Effects on Palladium(II) C–X Reductive Elimination
    Item type: Journal Article
    Bogdos , Michael K.; Roediger, Sven; Ruepp , Florian; et al. (2025)
    Journal of the American Chemical Society
    Reductive elimination is the key bond-forming elementary step in many transition metal-catalyzed reactions relevant to the synthesis of pharmaceuticals, materials and fine chemicals. Metal electronics, ancillary ligand sterics and metal complex coordination number have been identified as the primary factors which affect the rate of reductive elimination, but their relative importance has not been quantified. By studying a new class of palladacycles using kinetics, electrochemistry, DFT calculations and tools from causal inference, we reexamine the canonical model and find that a direct effect of coordination number on rate is unlikely. To address this contradiction, we propose an updated understanding based on mechanistic considerations, which accounts for our findings, the canonical understanding, and other observations in literature. Path coefficients calculated using mediation analysis allow the quantification of the effects of electronics, sterics and coordination number on the rate. Overall, we find that electronics and changes in coordination number exert the greatest influence on the rate, with the latter primarily acting through altering metal electronics. Finally, using this new-found knowledge, we were able to use the structures of complexes reported in the literature to calculate appropriate DFT descriptors and build a model capable of predicting the rate of reductive elimination for C–N, C–S and C–O bond formation with reasonable accuracy.
Publications 1 - 7 of 7