Peter Mayer

Ludwig-Maximilian-University of Munich, München, Bavaria, Germany

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Publications (572)

  • Zhen Li · Quan Chen · Peter Mayer · Herbert Mayr
    [Show abstract] [Hide abstract] ABSTRACT: The rates of the reactions of the arylsulfonyl substituted carbanions carrying α-chloro and α-bromo substituents 1a-e with quinone methides 2a-g and benzylidenemalonates 2h-i in DMSO were determined photometrically at 20 °C. The reactions were carried out under pseudo-first-order conditions, and the second-order rate constants were obtained as the slopes of the plots of the pseudo-first-order rate constants versus the concentrations of the reactants used in excess. The second-order rate constants correlate linearly with the parameters E of the reference electrophiles according to the linear free-energy relationship log k2(20 °C) = sN(N + E), which allowed to derive the nucleophile-specific parameters N and sN of the carbanions 1a-e. The resulting nucleophilicity parameters in the range 23 < N < 29 reveals the title compounds to be among the most reactive nucleophiles, so far integrated in our comprehensive nucleophilicity scale.
    Article · Jan 2017 · The Journal of Organic Chemistry
  • [Show abstract] [Hide abstract] ABSTRACT: A new oxidovanadium(IV) complex, 2[VOL(OH2)] CH3OH (1), was synthesized from the reaction of VO(acac)2 with a symmetric N,O-donor Schiff base ligand (H2L), in which H2L is 6,6'-((1E,1′E)-((2-hydroxypropane-1,3-diyl)bis(azanylylidene))bis(methanylylidene))bis(2-methoxyphenol). The compounds were characterized by elemental analysis and spectroscopic methods. The molecular structure of complex was determined by single-crystal X-ray analysis which indicated that the crystal packing of complex contains two independent mononuclear vanadium complexes connected together by several strong hydrogen bonding interactions. The EPR spectrum of powdered complex 1 at liquid helium temperature showed two intensive octets which proved to be associated with V⁴⁺ ions with 3d¹ electronic configuration. From EPR spectrum the values of the parameters: g|| = 1.9454 ± 0.0004, g⊥ = 1.9491 ± 0.0004, A|| = 0.0084 ± 0.0008 cm⁻¹ and A⊥ = 0.0033 ± 0.0006 cm⁻¹ were calculated for this complex. Complex 1 was employed as catalyst for oxidation of cyclooctene in the presence of H2O2 as oxidant. In order to obtain the suitable condition of catalytic oxidation, the effect of various parameters including the amount of the catalyst, temperature and solvent was studied. The results of catalytic studies showed that complex 1 can provide an effective and selective catalytic system for epoxidation of cyclooctene.
    Article · Dec 2016 · Journal of Molecular Structure
  • Elsa Follet · Peter Mayer · Guillaume Berionni
    [Show abstract] [Hide abstract] ABSTRACT: The isolation, characterization, and the first X-ray structures of a fluorenylium ion and its Lewis adducts with nitrogen- and phosphorus-centered Lewis bases are reported. Kinetics of the reactions of a series of fluorenylium ions with reference π-, σ-, and n-nucleophiles of various sizes and nucleophilicities allowed to elucidate the interplay between electronic and structural parameters on the electrophilicities of these planarized tertiary carbenium ions. Structure-reactivity correlations and extensive comparisons of their reactivities with those of di- and tri-arylcarbenium ions are described. Quantitative determination of the electrofugalities of fluorenylium ions revealed in which extent they are complementing tritylium ions as protecting groups and how their tuning is possible. Determination of the equilibrium constants of the Lewis adducts formation between pyridines of calibrated Lewis basicities and phenylfluorenylium and tritylium ions allowed to determine their Lewis acidities and to showcase the potential of these carbon-centered Lewis acids in catalysis.
    Article · Oct 2016 · Chemistry - A European Journal
  • Anna Skoczynska · Karin Lux · Peter Mayer · [...] · Elzbieta Budzisz
    [Show abstract] [Hide abstract] ABSTRACT: This paper presents the synthesis of two new (p-cymene)-ruthenium(II) complexes 3a,b with the bidentate coumarin ligands 2a,b. Both complexes were characterized by FTIR spectroscopy, ¹H NMR, ¹³C NMR, MS, elemental analysis and DFT calculations. The X-ray structure of complex 3a was also solved. The cytotoxic properties of both complexes were examined on human leukemia NALM-6 and HL-60 cells and melanoma WM-115 cells. The complexes possess higher cytotoxic activity than the ligands, but distinctive result is for complex 3b, which exhibited higher cytotoxic effect on WM-115 cells (IC50 = 60.2±7.8 μM) in comparison to carboplatin (IC50 = 422.2±50.2 μM). The results of DFT calculations performed at the BP86-D3/QZ4P level for Ru(II) complexes and Pd(II) complexes with the same ligands indicate that Pd(II) complexes are more lipophilic. Moreover the RP-TLC-Based Lipophilicity assessment was also performed.
    Article · Oct 2016
  • Manuel Guentner · Edgar Uhl · Peter Mayer · Henry Dube
    [Show abstract] [Hide abstract] ABSTRACT: The first example of a bis-Hemithioindigo (bis-HTI) based molecular receptor was realized. Its folding and selective binding affinity for aromatic guest molecules can precisely be controlled by visible light and heat. The thermodynamically stable state of the bis-HTI is the s-shaped planar Z,Z-configuration. After irradiation with 420 nm light only the E,Z-configuration is formed in a highly selective photoisomerization. The E,Z-isomer adopts a helical conformation because of the conscious implementation of repulsive sterical interactions. The E,Z-configured helix is able to recognize electron poor aromatic guests exclusively via polar aromatic interactions and also distinguishes between regioisomers. After heating the Z,Z-configuration is completely restored and the aromatic guest molecule is efficiently released.
    Article · Sep 2016 · Chemistry - A European Journal
  • [Show abstract] [Hide abstract] ABSTRACT: Controlling the internal motions of molecules by outside stimuli is a decisive task for the generation of responsive and complex molecular behavior and functionality. Light induced structural changes of photoswitches are of special high interest due to the ease of signal application and high repeatability. Typically photoswitches use one reaction coordinate in their switching process and change between two more or less defined states. Here we report on new twisted hemithioindigo photoswitches enabling two different reaction coordinates to be used for the switching process. Depending on the polarity of the solvent either complete single bond (in DMSO) or double bond (in cyclohexane) rotation can be induced by visible light. This mutual independent switching establishes an unprecedented two-dimensional control of intramolecular rotations in this class of photoswitches. The mechanistic explanation involves formation of highly polar twisted intramolecular charge-transfer species (TICT) in the excited state and is based on a large body of experimental quantifications, most notably ultrafast spectroscopy and quantum yield measurements in solvents of different polarity. The concept of pre-twisting in the ground state to open new independent reaction coordinates in the excited state should be transferable to other photoswitching systems.
    Article · Aug 2016 · Journal of the American Chemical Society
  • [Show abstract] [Hide abstract] ABSTRACT: New conjunctive β-silylated organometallic reagents of Li, Mg, and Zn are prepared and used for an expeditive construction of various polyfunctionalized 5-, 6-, and 7-membered heterocycles, such as furans, pyrroles, quinolines, benzo[b]thieno-[2,3-b]pyridine, naphthyridines, fused pyrazoles, and 2,3-dihydro-benzo[c]azepines.
    Article · Aug 2016 · ChemInform
  • Saloua Chelli · Konstantin Troshin · Peter Mayer · [...] · Herbert Mayr
    [Show abstract] [Hide abstract] ABSTRACT: Kinetics and mechanisms of the reactions of the β-dicarbonyl-substituted iodonium ylides 1(a-d) with several π-conjugated carbenium and iminium ions have been investigated. All reactions proceed with rate-determining attack of the electrophile at the nucleophilic carbon center of the ylides to give iodonium ions, which rapidly expel iodobenzene and undergo different subsequent reactions. The second-order rate constants k2 for the reactions of the iodonium ylides with benzhydrylium ions correlate linearly with the electrophilicity parameters E of the benzhydrylium ions, and thus follow the linear free energy relationship log k(20°C) = sN(N + E) (eq 1), where electrophiles are characterized by one parameter (E), while nucleophiles are characterized by two parameters: the nucleophilicity N and the susceptibility sN. The nucleophilicity parameters 4 < N < 8 for iodonium ylides 1(a-d) derived from these correlations show that substituting hydrogen for Ph-I+ at the carbanionic center of Meldrum's acid or dimedone, respectively, reduces the nucleophilicity by approximately ten orders of magnitude. The iodonium ylides 1(a-d) thus have similar nucleophilicities as pyrroles, indoles, and silylated enol ethers, and therefore should be suitable substrates in iminium-activated reactions. Good agreement of the measured rate constant for the cyclopropanation of the imidazolidinone-derived iminium ion 10a with the iodonium ylide 1a with the rate constant calculated by eq 1 suggests a stepwise mechanism, in which the initial nucleophilic attack of the iodonium ylide at the iminium ion is rate-determining. The reaction of cinnamaldehyde with iodonium ylide 1a catalyzed by (5S)-5-benzyl-2,2,3-trimethyl-imidazolidin-4-one (11a, MacMillan's first generation catalyst) gives the corresponding cyclopropane with an enantiomeric ratio of 70/30 and, thus, provides proof of principle that iodonium ylides are suitable substrates for iminium-activated cyclopropanations.
    Article · Jul 2016 · Journal of the American Chemical Society
  • Elsa Follet · Peter Mayer · Herbert Mayr
    [Show abstract] [Hide abstract] ABSTRACT: Rate and equilibrium constants for the reactions of indol-3-ylmethylium ions with triarylphosphines and pyridines were measured spectrophotometrically. The resulting Lewis acid-base adducts were characterized by NMR and X-ray crystallography. All rate constants, except those for the reactions of sterically hindered bis(indol-3-yl)methylium ion 1j with phosphines, agreed within a factor of 4 with those calculated by the correlation log k20 °C = sN(N + E) from previously reported electrophilicity parameters E for indol-3-ylmethylium ions and N and sN parameters for phosphines and pyridines. Lewis acidities (LA) of indol-3-ylmethylium ions were calculated from the correlation log K20 °C = LA + LB using the benzhydrylium-based Lewis basicities (LB) of phosphines and pyridines and the equilibrium constants for the reactions of these Lewis bases with indol-3-ylmethylium ions. The agreement of LA values derived from equilibrium constants of their reactions with different types of Lewis bases shows that indol-3-ylmethylium ions have a steric demand similar to the p- and m-substituted benzhydrylium ions. For some reactions of indol-3-ylmethylium ions with phosphines and pyridines, rate and equilibrium constants could be determined, which allowed us to calculate the Marcus intrinsic barriers and compare them with those for analogous reactions with the dicarbonyl(η5-cyclopentadienyl)-(η2-ethene)iron cation.
    Article · Jul 2016 · European Journal of Organic Chemistry
  • [Show abstract] [Hide abstract] ABSTRACT: The synthesis and structural characterization of trans-[IrCl(NO)(PtBu2H)2]BF4 (1) is reported. The title compound was prepared in good yield in the reaction of in situ-prepared trans-[IrCl(coe)(PtBu2H)2] (coe = cis-cyclooctene) with an appropriate amount of nitrosonium tetrafluoridoborate in dichloromethane at room temperature. Single crystals of 1 were grown from dichloromethane/diethyl ether and were analyzed by X-ray crystallography.
    Article · Jul 2016 · Zeitschrift für anorganische und allgemeine Chemie
  • [Show abstract] [Hide abstract] ABSTRACT: The origin of life is believed to have started with prebiotic molecules reacting along unidentified pathways to produce key molecules such as nucleosides. To date, a single prebiotic pathway to purine nucleosides had been proposed. It is considered to be inefficient due to missing regioselectivity and low yields. We report that the condensation of formamidopyrimidines (FaPys) with sugars provides the natural N-9 nucleosides with extreme regioselectivity and in good yields (60%). The FaPys are available from formic acid and aminopyrimidines, which are in turn available from prebiotic molecules that were also detected during the Rosetta comet mission. This nucleoside formation pathway can be fused to sugar-forming reactions to produce pentosides, providing a plausible scenario of how purine nucleosides may have formed under prebiotic conditions.
    Article · May 2016 · Science
  • Source
    Quan Chen · Peter Mayer · Herbert Mayr
    [Show abstract] [Hide abstract] ABSTRACT: The kinetics of the reactions of ethenesulfonyl fluoride (ESF) with sulfonium and pyridinium ylides were measured photometrically to determine the electrophilicity parameter of ESF according to the correlation lg k20 °C =sN (N+E). With E=-12.09, ESF is among the strongest Michael acceptors in our comprehensive electrophilicity scale, which explains its excellent performance in reactions with many nucleophiles. Its predicted usability as a reagent in electrophilic aromatic substitutions with electron-rich arenes was confirmed by uncatalyzed reactions with alkyl-substituted pyrroles.
    Full-text available · Article · May 2016 · Angewandte Chemie International Edition
  • Quan Chen · Peter Mayer · Herbert Mayr
    Article · May 2016
  • [Show abstract] [Hide abstract] ABSTRACT: The treatment of α-chiral secondary alkyl iodides with tBuLi at -100°C leads to the corresponding secondary alkyllithiums with high retention of configuration. Subsequent quenching with various electrophiles such as Bu2S2, DMF, MeOB(OR)2, Et2CO provides the desired products with retention of configuration. Furthermore a transmetalation with CuBr·P(OEt)3 allows also a retentive trapping with acid chlorides and ethylene oxide. The quenching of the resulting alkyllithiums with ClCO2Et furnishes stereoselectively syn- and anti-ethyl 2,3-dimethyl ester carboxylates (d.r.>94%). Related esters bearing three adjacent stereo-controlled centers (streotriads) have also been prepared. This method has been applied to the synthesis of the ant pheromone (±)-lasiol in 26% overall yield (4 steps) with d.r.=97:3 starting from commercially available cis-2,3-epoxybutane.
    Article · May 2016 · Chemistry - A European Journal
  • Source
    Saloua Chelli · Konstantin Troshin · Sami Lakhdar · [...] · Peter Mayer
    [Show abstract] [Hide abstract] ABSTRACT: In the title compound, C 23 H 25 ClO 4 , the cyclohexane ring adopts a chair conformation with the 4-methoxyphenyl substituent in an axial position and the chloro(4-methoxyphenyl)methyl substituent in an equatorial position. The packing features inversion dimers formed by pairs of C—H...O contacts and strands along [100] and [010] established by further C—H...O and C—H...Cl contacts, respectively.
    Full-text available · Article · Mar 2016
  • [Show abstract] [Hide abstract] ABSTRACT: Neue konjunktive β-silylierte organometallische Li-, Mg- und Zn-Reagentien wurden hergestellt und für den Aufbau einer Vielzahl von polyfunktionalisierten 5-, 6- und 7-gliedrigen Heterocyclen wie Furane, Pyrrole, Chinoline, Benzo[b]thieno[2,3-b]pyridin, Naphthyridine, kondensierte Pyrazole und 2,3-Dihydrobenzo[c]azepine verwendet. Die endständige Silylgruppe konnte in den meisten Heterocyclenklassen in neue Kohlenstoff-Kohlenstoff-Bindungen umgewandelt werden.
    Article · Mar 2016 · Angewandte Chemie
  • [Show abstract] [Hide abstract] ABSTRACT: New conjunctive β-silylated organometallic reagents of Li, Mg, and Zn have been prepared and used for an expeditive construction of various polyfunctionalized 5-, 6-, and 7-membered heterocycles, such as furans, pyrroles, quinolines, benzo[b]thieno-[2,3-b]pyridine, naphthyridines, fused pyrazoles, and 2,3-dihydro-benzo[c]azepines. The latent silyl group has been converted into various carbon-carbon bonds in most heterocycle types.
    Article · Mar 2016 · Angewandte Chemie International Edition
  • Hans-Christian Böttcher · Peter Mayer
    [Show abstract] [Hide abstract] ABSTRACT: The synthesis and structural characterization of trans-[RhCl(NO)(PtBu2H)2]BF4 (2) is reported. The title compound could easily be prepared in good yields by a kind of “bridge-splitting” reaction of [{Rh(μ-Cl)(PtBu2H)2}2] (1) with an appropriate amount of nitrosonium tetrafluoridoborate in dichloromethane at room temperature. Single crystals of 2 were grown from dichloromethane/diethyl ether and were analyzed by X-ray crystallography.
    Article · Feb 2016 · Zeitschrift für anorganische und allgemeine Chemie
  • Saloua Chelli · Konstantin Troshin · Sami Lakhdar · [...] · Peter Mayer
    File available · Data · Feb 2016
  • Saloua Chelli · Konstantin Troshin · Sami Lakhdar · [...] · Peter Mayer
    File available · Data · Feb 2016

Publication Stats

7k Citations

Institutions

  • 2014
    • Ludwig-Maximilian-University of Munich
      • Department of Chemistry
      München, Bavaria, Germany
  • 2007
    • University of Rostock
      • Inorganic Chemistry
      Rostock, Mecklenburg-Vorpommern, Germany
    • Universitätsklinikum Jena
      Jena, Thuringia, Germany
  • 2000-2004
    • Technische Universität München
      München, Bavaria, Germany
    • University Hospital München
      München, Bavaria, Germany
  • 2003
    • Dongguk University
      • Department of Chemistry
      Sŏul, Seoul, South Korea