• A simple and efficient method for the preparation of 5-hydroxy-3-acyltetramic acids.

      Trenner, Johanna; Prusov, Evgeny V; Helmholtz Centre for infection research, Inhoffenstr. 7, D-38124 Braunschweig, Germany. (2015)
      Oxidation of the bisenolates of 3-acyltetramic acid to the corresponding 5-hydroxylated compounds using molecular oxygen is reported. The deprotection of the resulting compounds was also achieved.
    • Stereoselective total synthesis of etnangien and etnangien methyl ester.

      Li, Pengfei; Li, Jun; Arikan, Fatih; Ahlbrecht, Wiebke; Dieckmann, Michael; Menche, Dirk; Institut für Organische Chemie, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany. (2010-04-16)
      A highly stereoselective joint total synthesis of the potent polyketide macrolide antibiotics etnangien and etnangien methyl ester was accomplished by a convergent strategy and proceeds in 23 steps (longest linear sequence). Notable synthetic features include a sequence of highly stereoselective substrate-controlled aldol reactions to set the characteristic assembly of methyl- and hydroxyl-bearing stereogenic centers of the propionate portions, an efficient diastereoselective Heck macrocyclization of a deliberately conformationally biased precursor, and a late-stage introduction of the labile side chain by means of a high-yielding Stille coupling of protective-group-free precursors. Along the way, an improved, reliable protocol for a Z-selective Stork-Zhao-Wittig olefination of aldehydes was developed, and an effective protocol for a 1,3-syn reduction of sterically particularly hindered beta-hydroxy ketones was devised. Within the synthetic campaign, a more detailed understanding of the intrinsic isomerization pathways of these labile natural products was elaborated. The expedient and flexible strategy of the etnangiens should be amenable to designed analogues of these RNA-polymerase inhibitors, thus enabling further exploration of the promising biological potential of these macrolide antibiotics.
    • Synthesis of the northern hemisphere of amphidinolide H2

      Liesener, F.P.; Jannsen, U.; Kalesse, M. (Thieme, 2006)
    • Synthesis of the spiroketal core of integramycin.

      Prusov, Evgeny V; Department of Medicinal Chemistry, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124 Braunschweig, Germany (2013)
      A concise synthetic strategy towards the spiroketal core of the HIV-integrase inhibitor integramycin (1) was developed. The required ketone precursor was efficiently constructed from two simple and easily accessible subunits by means of a hydrozirconation/copper catalyzed acylation reaction. The effects of different protecting groups on the spiroketalization step were also investigated.
    • Thiourea-catalyzed direct reductive amination of aldehydes

      Menche, Dirk; Arikan, Fatih (Thieme, 2007-09-25)
    • Total Synthesis and Structure Revision of Halioxepine.

      Poock, Caroline; Kalesse, Markus; HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany. (Wiley, 2020-11-20)
      The first total synthesis of halioxepine is accomplished using a 1,4-addition for constructing the quaternary center at C10 and a halo etherification for the generation of the tertiary ether at C7. The correct structure of halioxepine was determined by assembling different enantiomeric building blocks and by changing the relative configuration between C10 and C15.
    • Total synthesis of antibiotics: recent achievements, limitations, and perspectives.

      Prusov, Evgeny V; Helmholtz Zentrum für Infektionsforschung, Braunschweig, Germany. Evgeny.Prusov@helmholtz-hzi.de (2013-04)
      Several recently accomplished total syntheses of antibiotic natural products were summarized in this review in order to present current trends in this area of research. Compounds from different substance classes, including polyketide, depsipeptide, polyketide-polypeptide hybrid, and saccharide, were chosen to demonstrate the advancement in both chemical methodology and corresponding synthetic strategy.
    • Total Synthesis of Nannocystin Ax.

      Poock, Caroline; Kalesse, Markus; Hemholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7, 38124 Braunschweig, Germany. (2017-09-01)
      The total synthesis of nannocystin Ax in an overall yield of 11% with 14 steps as the longest linear sequence is reported. Nannocystin Ax is a cytotoxic 21-membered depsipeptide and was isolated from the myxobacterial genus Nannocystis sp. The synthesis uses a vinylogous Horner-Wadsworth-Emmons reaction (HWE) and a vinylogous Mukaiyama aldol reaction (VMAR) as the key steps for the construction of the polyketide fragment. The macrocycle was closed via a macrolactamization reaction using COMU.
    • Tris(acetylacetonato) Iron(III): Recent Developments and Synthetic Applications

      Lübken, Dennis; Saxarra, Marius; Kalesse, Markus; HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany. (Thieme, 2018-11-27)
      Tris(acetylacetonato) iron(III) [Fe(acac)3] is an indispensable reagent in synthetic chemistry. Its applications range from hydrogen atom transfer to cross-coupling reactions and to use as a Lewis acid. Consequently, the exceptional utility of Fe(acac)3 has been demonstrated in several total syntheses. This short review summarizes the applications of Fe(acac)3 in methodology and catalysis and highlights its use for the synthesis of medicinally relevant structures and in natural product syntheses.