Peter Mayer

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

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Publications (443)1174.45 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Astellatol and nitidasin belong to a subset of sesterterpenoids that share a sterically encumbered trans-hydrindane motif with an isopropyl substituent. In addition, these natural products feature intriguing polycyclic ring systems, posing significant challenges for chemical synthesis. Herein, the evolution of our stereoselective strategy for isopropyl trans-hydrindane sesterterpenoids is detailed. These endeavors included the synthesis of several building blocks, enabling studies toward all molecules of this terpenoid subclass, and of advanced intermediates of our initial route toward a biomimetic synthesis of astellatol. These findings provided the basis for a second-generation and a third-generation approach toward astellatol that eventually culminated in the enantioselective total synthesis of (-)-nitidasin. In particular, a series of substrate-controlled transformations to install the ten stereogenic centers of the target molecule was orchestrated and the carbocyclic backbone was forged in a convergent fashion. Furthermore, the progress toward the synthesis of astellatol is disclosed and insights into some observed yet unexpected diastereoselectivities by detailed quantum-mechanical calculations are provided. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
    Chemistry - A European Journal 08/2015; DOI:10.1002/chem.201501423 · 5.70 Impact Factor
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    ABSTRACT: Eight substituted aryl(indol-3-yl)methylium tetrafluoroborates 3(a-h)-BF4 and three bis(indol-3-yl)methylium tetrafluoroborates 3(i-k)-BF4 have been synthesized and characterized by NMR spectroscopy and X-ray crystallography. Their reactions with π-nucleophiles 8(a-j) (silylated enol ethers, and ketene acetals) were studied kinetically using photometric monitoring at 20 °C. The resulting second-order rate constants were found to follow the correlation log k (20 °C) = sN(N + E), in which nucleophiles are characterized by the two solvent-dependent parameters N and sN, and electrophiles are characterized by one parameter, E. From the previously reported N and sN parameters of the employed nucleophiles, and the measured rate constants, the electrophilicities of the indol-3-ylmethylium ions 3(a-k) were derived and used to predict potential nucleophilic reaction partners. A discrepancy between published rate constants for the reactions of morpholine and piperidine with the (2-methylindol-3-yl)phenylmethylium ion 3h and that calculated from E, N and sN was analyzed and demonstrated to be due to a mistake of the value reported in the literature.
    The Journal of Organic Chemistry 07/2015; DOI:10.1021/acs.joc.5b01298 · 4.64 Impact Factor
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    ABSTRACT: A convenient synthesis of cyclometalated complexes [{Rh(μ-Cl)(C N)2}2] [C N = ppy, 2-phenylpyridinato (2); C N = ptpy, 2-(p-tolyl)pyridinato (3); 4-Clppy = 4-chloro-2-phenylpyridinato (4)] at room temperature is described. The compounds were obtained by the oxidative addition reaction of the corresponding 2-phenylpyridines to [{Rh(μ-Cl)(coe)2}2] (1) (coe = cis-cyclooctene) in dichloromethane solution. The rate of the reaction seems to depend on the electronic influence of the substituents on the phenyl rings of the corresponding 2-phenylpyridines. The analogous iridium complex of 1 reacted markedly only at higher temperatures in suitable solvents under cyclometalation. The molecular structure of the new compound 4 was additionally confirmed by an X-ray diffraction study.
    Zeitschrift für anorganische Chemie 07/2015; DOI:10.1002/zaac.201500527 · 1.25 Impact Factor
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    ABSTRACT: Aryl sulfonamides are a widely used drug class for the inhibition of carbonic anhydrases. In the context of our program of photochromic pharmacophores we were interested in the exploration of azobenzene-containing sulfonamides to block the catalytic activity of human carbonic anhydrase II (hCAII). Herein, we report the synthesis and in vitro evaluation of a small library of nine photochromic sulfonamides towards hCAII. All molecules are azobenzene-4-sulfonamides, which are substituted by different functional groups in the 4´-position and were characterized by X-ray crystallography. We aimed to investigate the influence of electron-donating or electron-withdrawing substituents on the inhibitory constant K i. With the aid of an hCAII crystal structure bound to one of the synthesized azobenzenes, we found that the electronic structure does not strongly affect inhibition. Taken together, all compounds are strong blockers of hCAII with K i = 25-65 nM that are potentially photochromic and thus combine studies from chemical synthesis, crystallography and enzyme kinetics.
    Beilstein Journal of Organic Chemistry 07/2015; 11:1129-35. DOI:10.3762/bjoc.11.127 · 2.80 Impact Factor
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    ABSTRACT: In the crystal, molecules of the centrosymmetric title compound, C 12 H 4 Br 2 F 4 N 2 , are linked into strands along [011] by weak C—H...F contacts. Furthermore, the molecules are π–π stacked with perpendicular ring distances of 3.4530 (9) Å.
    07/2015; 71(7):o459-o460. DOI:10.1107/S2056989015010622
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    ABSTRACT: Reaction of [{Ir(μ-Cl)(coe)2}2] (1; coe = cis-cyclooctene) with 4 equiv. of PtBu2Ph in CH2Cl2 at ambient temperature resulted in oxidative addition of one phosphane ligand affording the known cyclometalated IrIII complex [IrCl(H)(PtBu2C6H4-κ2P,C)(PtBu2Ph)] (2) in high yield. Compound 2 exhibits a coordinatively unsaturated five-coordinate 16 VE species, and its reactivity towards strong π-acceptor ligands is investigated. Reaction of 2 with CO resulted in addition of the CO ligand and inversion of cyclometalation to give known IrI complex trans-[IrCl(CO)(PtBu2Ph)2] (3). In a similar manner, 1 reacted with nitrosonium tetrafluoridoborate affording the new complex salt [IrCl(NO)(PtBu2Ph)2][BF4] (4), which is isoelectronic with 3. Compounds 2 and 4 were characterized by spectroscopic methods as well as by X-ray crystallography confirming their molecular structures.
    Berichte der deutschen chemischen Gesellschaft 06/2015; DOI:10.1002/ejic.201500363
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    ABSTRACT: In the title compound, [CuCl2(C7H7NO2)2], the square-planar-coordinated CuII ion lies on a centre of symmetry and is bonded to two monodentate methyl­isonicotinate ligands through their N atoms and by two chloride ligands. The mol­ecules pack in a herringbone pattern. Perpendicular to [100] there are weak inter­molecular C-HCl and C-HO contacts. Along [100] there are infinite chains of edge-sharing octa­hedra linked through the chlorido ligands
    05/2015; 71(5):m112-m113. DOI:10.1107/S205698901500729X
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    ABSTRACT: Two new Cu(II) complexes were synthesized from Cu(NO 3) 2 Á3H 2 O and salan ligands, H 2 [H 4 ]L 1 and H 2 [H 4 ]L 2 (H 2 [H 4 ]L 1 = N,N 0 -bis(o-hydroxybenzyl)-1,2-diaminocyclohexane; H 2 [H 4 ]L 2 = N,N 0 -bis(o-hydroxybro-mobenzyl)1,2-diaminocyclohexane). They were character-ized by various spectroscopic methods and structures of the complexes determined by X-ray diffraction analyses. Interestingly, H 2 [H 4 ]L 1 coordinates to copper centers as monoanionic in a tetradentate mode in complex 1, [Cu(H[H 4 ]L 1)] 2 Á2NO 3 Á2H 2 O, whereas H 2 [H 4 ]L 2 behaves as a dianionic ligand in complex 2, [Cu([H 4 ]L 2)] 2 Á0.4H 2 O, via the O,N,N 0 ,O 0 -donor atoms. The asymmetric unit in the complexes is dimerized about a center of inversion by asymmetric bridging of the phenoxide-O atom between two metal centers. The electronic spectra studies of the complexes in various solvents with different coordination numbers proved the stability of the dinuclear complexes in solvents other than DMSO and DMF. Complexes 1 and 2 showed high catalytic activities with good-to-excellent selectivities in the oxidation of olefins, benzyl alcohol and ethyl benzene with H 2 O 2 in acetonitrile. A probable mechanism is discussed.
    Transition Metal Chemistry 02/2015; · 1.40 Impact Factor
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    ABSTRACT: Two new Cu(II) complexes were synthesized from Cu(NO3)2·3H2O and salan ligands, H2[H4]L1 and H2[H4]L2 (H2[H4]L1 = N,N′-bis(o-hydroxybenzyl)-1,2-diaminocyclohexane; H2[H4]L2 = N,N′-bis(o-hydroxybromobenzyl)1,2-diaminocyclohexane). They were characterized by various spectroscopic methods and structures of the complexes determined by X-ray diffraction analyses. Interestingly, H2[H4]L1 coordinates to copper centers as monoanionic in a tetradentate mode in complex 1, [Cu(H[H4]L1)]2·2NO3·2H2O, whereas H2[H4]L2 behaves as a dianionic ligand in complex 2, [Cu([H4]L2)]2·0.4H2O, via the O,N,N′,O′-donor atoms. The asymmetric unit in the complexes is dimerized about a center of inversion by asymmetric bridging of the phenoxide-O atom between two metal centers. The electronic spectra studies of the complexes in various solvents with different coordination numbers proved the stability of the dinuclear complexes in solvents other than DMSO and DMF. Complexes 1 and 2 showed high catalytic activities with good-to-excellent selectivities in the oxidation of olefins, benzyl alcohol and ethyl benzene with H2O2 in acetonitrile. A probable mechanism is discussed.
    Transition Metal Chemistry 02/2015; 40(3). DOI:10.1007/s11243-015-9913-6 · 1.40 Impact Factor
  • ChemInform 02/2015; 46(6):no-no. DOI:10.1002/chin.201506230
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    ABSTRACT: Aus Thienyl- bzw. Furylboronsäureestern und Aryllithium-Verbindungen hergestellte Bor-at-Komplexe wurden isoliert und durch Röntgenstrukturanalyse charakterisiert. Die Produkte und Mechanismen ihrer Reaktionen mit Carbenium- und Iminium-Ionen wurden analysiert. Durch UV/Vis-spektroskopische Verfolgung der Kinetik dieser Reaktionen wurde der Einfluss der Aryl-Substituenten, der Diol-Liganden (Pinakol, Ethylenglykol, Neopentylglykol, Brenzkatechin) und der Gegenionen auf die nucleophile Reaktivität der Bor-at-Komplexe untersucht. Eine Hammett-Korrelation bestätigte die polare Natur ihrer Reaktionen mit Benzhydrylium-Ionen, und die Korrelation lg k(20 °C)=sN(E+N) wurde verwendet, um die Nucleophilie der Bor-at-Komplexe zu bestimmen und mit der anderer Borate und Boronate zu vergleichen. Die Neopentylglykol- und Ethylenglykol-Derivate sind 104-mal reaktiver als die Pinakol- und Brenzkatechin-Derivate.
    Angewandte Chemie 01/2015; 127(9). DOI:10.1002/ange.201410562
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    ABSTRACT: Boron ate complexes derived from thienyl and furyl boronic esters and aryllithium compounds have been isolated and characterized by X-ray crystallography. Products and mechanisms of their reactions with carbenium and iminium ions have been analyzed. Kinetics of these reactions were monitored by UV/Vis spectroscopy, and the influence of the aryl substituents, the diol ligands (pinacol, ethylene glycol, neopentyl glycol, catechol), and the counterions on the nucleophilic reactivity of the boron ate complexes were examined. A Hammett correlation confirmed the polar nature of their reactions with benzhydrylium ions, and the correlation lg k(20 °C)=sN(E+N) was employed to determine the nucleophilicities of the boron ate complexes and to compare them with those of other borates and boronates. The neopentyl and ethylene glycol derivatives were found to be 104 times more reactive than the pinacol and catechol derivatives.
    Angewandte Chemie International Edition 01/2015; 54(9). DOI:10.1002/anie.201410562 · 11.26 Impact Factor
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    ABSTRACT: The ambient pressure phase of silicon disulfide (NP-SiS 2), published in 1935, is orthorhombic and contains chains of distorted, edge-sharing SiS 4 tetrahedra. The first high pressure phase, HP3-SiS 2 , published in 1965 and quenchable to ambient conditions, is tetragonal and contains distorted corner-sharing SiS 4 tetrahedra. Here, we report on the crystal structures of two monoclinic phases, HP1-SiS 2 and HP2-SiS 2 , which can be considered as missing links between the orthorhombic and the tetragonal phase. Both monoclinic phases contain edge-as well as corner-sharing SiS 4 tetrahedra. With increasing pressure, the volume contraction (−ΔV/V) and the density, compared to the orthorhombic NP-phase, increase from only edge-sharing tetrahedra to only corner-sharing tetrahedra. The lattice and the positional parameters of NP-SiS 2 , HP1-SiS 2 , HP2-SiS 2 , and HP3-SiS 2 were derived in good agreement with the experimental data from group−subgroup relationships with the CaF 2 structure as aristotype. In addition, the Raman spectra of SiS 2 show that the most intense bands of the new phases HP1-SiS 2 and HP2-SiS 2 (408 and 404 cm −1 , respectively) lie between those of NP-SiS 2 (434 cm −1) and HP3-SiS 2 (324 cm −1). Density functional theory (DFT) calculations confirm these observations.
    Inorganic Chemistry 01/2015; 54(4). DOI:10.1021/ic501825r · 4.79 Impact Factor
  • Martin Olbrich · Peter Mayer · Dirk Trauner
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    ABSTRACT: A synthetic strategy toward the intriguing hydrocarbon nanorod polytwistane is outlined. Our approach aims toward the polymerization of acetylene starting from precursors that would provide a helical bias for the formation of polytwistane. Both transition metal catalyzed and radical polymerizations were investigated. Two potential initiator molecules were synthesized that could be used for either approach. Although the intended regioselectivities were not observed, unusual organopalladium complexes and numerous compounds with novel carbon skeletons were obtained.
    The Journal of Organic Chemistry 12/2014; 80(4). DOI:10.1021/jo502618g · 4.64 Impact Factor
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    ABSTRACT: A new Mn(II) coordination polymer, [Mn (L1)2(NCS)2]n (1) [L1=3,4-bis(4-pyridyl)-5-(2-pyridyl)-1,2,4-triazole] was synthesized by the reaction of ligand L1 and mixtures of manganese(II) acetate and potassium thiocyanate using the heat gradient method. Compound 1 has been characterized by IR spectroscopy, elemental analyses and X-ray crystallography. The crystal structure of compound 1 was determined by single-crystal X-ray diffraction and shows a new interesting one-dimensional coordination polymer. Nanostructures of compound 1 have been synthesized by sonochemical method. The products were characterized by X-ray powder diffraction, scanning electron microscopy (SEM), and IR spectroscopy. The thermal stability of nano particles of compound 1 was studied by thermal gravimetric and differential thermal analyses. Copyright © 2014 Elsevier B.V. All rights reserved.
    Ultrasonics Sonochemistry 11/2014; 24. DOI:10.1016/j.ultsonch.2014.11.011 · 4.32 Impact Factor
  • Hans-Christian Böttcher · Peter Mayer
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    ABSTRACT: The reaction of [{Ir(mu-Cl)(coe)(2)}(2)] (coe = cis-cyclooctene) with triphenylphosphane (molar ratio of Jr to P = 1: 3) in dichloromethane at room temperature afforded after a short reaction time the cyclometallated complex [IrCl(H)(C6H4PPh2)(PPh3)(2)] (1) in almost quantitative yield. The molecular structure of the title compound 1 was determined by an X-ray diffraction study.
    Zeitschrift fur Naturforschung B 11/2014; 69b(11-12):1237-1240. DOI:10.5560/ZNB.2014-4160 · 0.77 Impact Factor
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    ABSTRACT: X-Ray structures of enamines and iminium ions derived from 2-tritylpyrrolidine (Maruoka catalyst) and 2-triphenylsilylpyrrolidine (Bolm-Christmann-Strohmann catalyst) have been determined. Kinetic investigations showed that enamines derived from phenylacetaldehyde and pyrrolidine (R = H) or 2-(triphenylsilyl)pyrrolidine (R = SiPh3) have similar reactivities toward benzhydryl cations Ar2CH+ (reference electrophiles) while the corresponding enamine derived from 2-tritylpyrrolidine (R = CPh3) is 26 times less reactive. The rationalization of this phenomenon by negative hyperconjugative interaction of the trityl group with the lone pair of the enamine nitrogen is supported by the finding that the trityl group in the 2-position of the pyrrolidine increases the electrophilic reactivity of iminium ions derived from cinnamaldehyde by a factor of 12. Consequences of these observations for the rationalization of the reactivity of the Jørgensen-Hayashi catalyst (diphenylprolinol trimethylsilyl ether) are discussed.
    Journal of the American Chemical Society 09/2014; 136(40). DOI:10.1021/ja508065e · 11.44 Impact Factor
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    ABSTRACT: The reaction of [Ru-3(CO)(12)] with pivalic acid in acetonitrile afforded the coordinatively unsaturated complex [{Ru-2(mu-O(2)CtBu)(2)(CO)(4)}(n)] (1) for which a so far unknown polymeric structure is assumed. Compound 1 showed in the solid as well as dissolved in non-polar aliphatic solvents and carbon tetrachloride, respectively, a deep violet color. In common organic solvents 1 is readily dissolved resulting in solutions exhibiting a yellow to orange color. On the one hand, in such solutions the polymeric structure of 1 is broken resulting in distinct compounds as the Ru-2(mu-O(2)CtBu)(2)(CO)(4) units coordinate two monodentate solvent molecules, as shown for [Ru-2(mu-(O2CBu)-Bu-t)(2)(CO)(4)(py)(2)] (3, py pyridine), or they coordinate ligands like phosphanes, as shown for [Ru-2(mu-O(2)CtBu)(2)(CO)(4)(PtBu2H)(2)] (4). On the other hand, in solutions of 1 the Ru2 frameworks are linked by coordination of multidentate solvent molecules resulting in a coordination polymer which was confirmed by the crystal structure determination of [{Ru-2(mu-O(2)CtBu)(2)(CO)(4)(HOC2H4OEt)}(n)] (2). (c) 2014 Elsevier B. V. All rights reserved.
    Journal of Organometallic Chemistry 09/2014; 767:160–164. DOI:10.1016/j.jorganchem.2014.05.032 · 2.17 Impact Factor
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    ABSTRACT: A short total synthesis of the published structure of racemic trichodermatide A is reported. Our synthesis involves a Knoevenagel condensation/Michael addition sequence, followed by the formation of tricyclic hexahydroxanthene-dione and a diastereoselective bis-hydroxylation. The final product, the structure of which was confirmed by X-ray crystallography, has NMR spectra that are very similar but not identical to those of the isolated natural product. Quantum chemically computed 13C shifts agree well with the present NMR measurements.
    The Journal of Organic Chemistry 08/2014; 79(20). DOI:10.1021/jo501206k · 4.64 Impact Factor
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    ABSTRACT: Nitidasin, ein komplexes Sesterterpenoid mit einem seltenen 5-8-6-5-Kohlenstoffgerüst, wurde aus dem peruanischen Naturheilmittel “Hercampuri” isoliert und ist ein Vertreter einer kleinen Gruppe von polycyclischen Sesterterpenoiden, die eine trans-Hydrindaneinheit mit einem Isopropylsubstituenten aufweisen. Als erstes Ergebnis unseres allgemeinen Ansatzes zur Synthese solcher Naturstoffe stellen wir die Totalsynthese der Titelverbindung vor. Die Schlüsselsequenz unserer stereoselektiven und konvergenten Route besteht aus der Addition einer komplexen Alkenyllithiumverbindung an ein trans-Hydrindanon, einer chemoselektiven Epoxidierung und einer Ringschlussmetathese.
    Angewandte Chemie 08/2014; 126(32). DOI:10.1002/ange.201403605

Publication Stats

4k Citations
1,174.45 Total Impact Points

Institutions

  • 2001–2015
    • Ludwig-Maximilians-University of Munich
      • • Department of Chemistry
      • • Faculty of Chemistry and Pharmacy
      • • Department of Biochemistry
      München, Bavaria, Germany
  • 2001–2014
    • Technische Universität München
      • Department of Biochemistry
      München, Bavaria, Germany
  • 2000–2014
    • University Hospital München
      München, Bavaria, Germany
  • 2007
    • Technische Universität Braunschweig
      • Faculty of Life Sciences
      Brunswyck, Lower Saxony, Germany
  • 2006–2007
    • University of Rostock
      • Inorganic Chemistry
      Rostock, Mecklenburg-Vorpommern, Germany
  • 2005
    • Nelson Mandela Metropolitan University
      • Department of Chemistry
      Port Elizabeth, Eastern Cape, South Africa
  • 2004
    • Port Elizabeth Museum
      Port Elizabeth, Eastern Cape, South Africa
  • 1999
    • University of Freiburg
      Freiburg, Baden-Württemberg, Germany