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ABSTRACT: Subtle noncovalent forces such as π-π interactions play an import role in the folding of biological macromolecules such as DNA and proteins. We describe here a system where such interactions on the outside of a molecular capsule trigger a selective change of its structure as a self-assembled receptor.
Journal of the American Chemical Society 02/2012; 134(6):2914-7. · 9.91 Impact Factor
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Angewandte Chemie International Edition 12/2011; 50(50):12003-7. · 13.45 Impact Factor
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Angewandte Chemie International Edition 10/2011; · 13.45 Impact Factor
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ABSTRACT: The synthesis of an azo-benzene glycoluril supergelator is reported. The control over the gel/sol state can be accomplished by irradiation and heat, but also (in a unidirectional sense) by incorporation of the glycoluril into a more stable supramolecular assembly.
Chemical Communications 07/2011; 47(26):7341-3. · 6.17 Impact Factor
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ABSTRACT: Platencin is a novel antibiotic which is active against multiresistant pathogens. We describe efficient syntheses of three platencin analogues of varying activities which allow further conclusions about the pharmacophoric part of the molecule. The unnatural antibiotic iso-platencin, which is about as active as natural platencin, but much more selective, was identified as a new lead structure.
Chemistry 08/2010; 16(31):9616-22. · 5.93 Impact Factor
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ABSTRACT: The first total syntheses of the novel 3,5,5,7-sesquiterpenoids (+)-Echinopine A (1) and B (2) were achieved. Thereby the proposed structures were confirmed, and the absolute stereochemistry was determined. The key features are (1) the stereoselective installation of the vinyl-moiety on the concave side of the bicyclo[3.3.0]octane core via Myers' [3,3]-sigmatropic rearrangement, (2) the finding that the substituent on the C7 position next to the ketone can be epimerized to the desired concave face under basic conditions, (3) the closure of the highly strained seven-membered ring via RCM, and (4) the unusual C2-homologation of a vinyltriflate with a ketene silyl acetal.
Organic Letters 10/2009; 11(22):5306-9. · 5.86 Impact Factor
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ABSTRACT: Within 1 year, platencin, a recently discovered antibiotic, has become a highly competitive synthetic target, due to its promising bioactivity and its unusual complex molecular architecture. Herein, a particularly concise total synthesis of platencin starting from inexpensive perillaldehyde is described. The key features of this approach are (1) a highly diastereoselective Diels-Alder reaction with Rawal's dieneforming the first all-carbon quaternary center, (2) a ring-closing metathesis to generate the strained tricylic skeleton, (3) a hydration/dehydration strategy to efficiently shift the endocyclic alkene to the exoposition, and (4) a 1,4-addition of a hindered ketone enolate to methyl acrylate to create the second all-carbon quaternary center. In view of the brevity (nine linear steps) and the overall yield of 10%, our synthesis compares favorably with all the previous ones.
The Journal of Organic Chemistry 05/2009; 74(8):2937-41. · 4.45 Impact Factor
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Angewandte Chemie International Edition 08/2008; 47(33):6199-200. · 13.45 Impact Factor
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Angewandte Chemie 03/2008; 120(14):2582 - 2590.
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ABSTRACT: In modern drug discovery, antibodies or libraries of simple synthetic organic compounds, mostly of heterocyclic origin, are favored. Natural products play an increasingly inferior role as they are considered structurally too complex, limited in quantity, and difficult to synthesize, manipulate, and derivatize. Thus it was a sensation when a Merck research group reported that classical screening of metabolites from Streptomyces platensis has unearthed a low-molecular-weight organic compound with remarkable antibiotic properties.
Angewandte Chemie International Edition 02/2008; 47(14):2548-55. · 13.45 Impact Factor
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Angewandte Chemie International Edition 02/2007; 46(42):8074-5. · 13.45 Impact Factor
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Angewandte Chemie International Edition 02/2007; 46(15):2690-3. · 13.45 Impact Factor
