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Publikationen - Natur- und Wirkstoffchemie

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Publikation

Lima, C. G. S.; Ali, A.; van Berkel, S. S.; Westermann, B.; Paixão, M. W.; Emerging approaches for the synthesis of triazoles: beyond metal-catalyzed and strain-promoted azide–alkyne cycloaddition Chem. Commun. 51, 10784-10796, (2015) DOI: 10.1039/c5cc04114g

Metal-free 1,3-dipolar cycloaddition reactions have proven to be a powerful tool for the assembly of key heterocycles, in particular diversely functionalized 1,2,3-triazoles. A number of metal-free (3+2)-cycloaddition approaches have been developed up to date with the aim to circumvent the use of metal catalysts allowing these reactions to take place in biological systems without perturbation of the naturally occurring processes. This feature article specifically provides an overview of emerging metal-free synthetic routes, and their mechanistic features, in the formation of functionalized 1,2,3-triazoles.
Publikation

Lima, C. G. S.; Ali, A.; van Berkel, S. S.; Westermann, B.; Paixão, M. W.; Correction: Emerging approaches for the synthesis of triazoles: beyond metal-catalyzed and strain-promoted azide–alkyne cycloaddition Chem. Commun. 51, 12139-12139, (2015) DOI: 10.1039/C5CC90314A

Correction for 'Emerging approaches for the synthesis of triazoles: beyond metal-catalyzed and strain-promoted azide–alkyne cycloaddition' by Carolina G. S. Lima et al., Chem. Commun., 2015, 51, 10784–10796.
Publikation

Schäffler, I.; Steiner, K. E.; Haid, M.; van Berkel, S. S.; Gerlach, G.; Johnson, S. D.; Wessjohann, L.; Dötterl, S.; Diacetin, a reliable cue and private communication channel in a specialized pollination system Sci. Rep. 5, 12779, (2015) DOI: 10.1038/srep12779

The interaction between floral oil secreting plants and oil-collecting bees is one of the most specialized of all pollination mutualisms. Yet, the specific stimuli used by the bees to locate their host flowers have remained elusive. This study identifies diacetin, a volatile acetylated glycerol, as a floral signal compound shared by unrelated oil plants from around the globe. Electrophysiological measurements of antennae and behavioural assays identified diacetin as the key volatile used by oil-collecting bees to locate their host flowers. Furthermore, electrophysiological measurements indicate that only oil-collecting bees are capable of detecting diacetin. The structural and obvious biosynthetic similarity between diacetin and associated floral oils make it a reliable cue for oil-collecting bees. It is easily perceived by oil bees, but can’t be detected by other potential pollinators. Therefore, diacetin represents the first demonstrated private communication channel in a pollination system.
Publikation

Brauch, S.; van Berkel, S. S.; Westermann, B.; Higher-order multicomponent reactions: beyond four reactants Chem. Soc. Rev. 42, 4948-4962, (2013) DOI: 10.1039/C3CS35505E

Multicomponent reactions (MCRs) are by far the most successful class of reactions leading to high structural diversity and molecular complexity through a single transformation. As part of the ongoing search for pharmacologically active lead structures, the obtained structural diversity allows for the fast exploration of a large chemical space. Not surprisingly, the development of MCRs, leading to new structural frameworks or serving as key transformations in the total synthesis of natural products, has expanded rapidly over the last few decades. To date a multitude of new three- and four-component reactions have already been described; however, examples of “higher-order” MCRs where five or even more components are combined in a single reaction vessel are remarkably scarce. This tutorial review aims to critically describe the developments achieved in recent years, charting the ideas, challenges, and milestone reactions that were essential for the progress of this field.
Publikation

Westermann, B.; Dörner, S.; Brauch, S.; Schaks, A.; Heinke, R.; Stark, S.; van Delft, F. L.; van Berkel, S. S.; CuAAC-mediated diversification of aminoglycoside–arginine conjugate mimics by non-reducing di- and trisaccharides Carbohyd. Res. 371, 61-67, (2013) DOI: 10.1016/j.carres.2013.02.003

Di- and triguanidinylation of trehalose, sucrose, and melizitose has been achieved via a Huisgen-cycloaddition approach. They can serve as aminoglycoside–arginine conjugate mimics, which has been demonstrated by their biological profiles in assays against Bacillus subtilis. For comparative studies, tetraguanidinylated neamine and kanamycin derivatives have also been synthesized and evaluated
Publikation

van Berkel, S. S.; Bögels, B. G. M.; Wijdeven, M. A.; Westermann, B.; Rutjes, F. P. J. T.; Recent Advances in Asymmetric Isocyanide-Based Multicomponent Reactions Eur. J. Org. Chem. 2012, 3543-3559, (2012) DOI: 10.1002/ejoc.201200030

This review discusses the use of various isocyanides (regular, chiral, and convertible) in asymmetric multicomponent reactions. In particular, stereoselective Ugi and Passerini reactions are highlighted, as well as their applications in modular sequential reactions and natural product synthesis.Isocyanide‐based multicomponent reactions (IMCRs) can be considered one of the breakthrough reaction classes of the last century. Moreover, asymmetric IMCRs have recently developed into powerful reactions for the versatile synthesis of highly complex molecules. The progress made in the development of stereoselective Passerini and Ugi reactions has led to the advancement of catalytic asymmetric IMCRs. This review gives an overview of recent advances in the field of asymmetric IMCRs with a focus on stereoselective α‐additions of isocyanides. In addition, the use of convertible isocyanides in stereoselective cascade IMCRs is covered and future opportunities and potential applications of (asymmetric) IMCRs are briefly discussed.
Publikation

Brauch, S.; Henze, M.; Osswald, B.; Naumann, K.; Wessjohann, L. A.; van Berkel, S. S.; Westermann, B.; Fast and efficient MCR-based synthesis of clickable rhodamine tags for protein profiling Org. Biomol. Chem. 10, 958-965, (2012) DOI: 10.1039/C1OB06581E

Protein profiling probes are important tools for studying the composition of the proteome and as such have contributed greatly to the understanding of various complex biological processes in higher organisms. For this purpose the application of fluorescently labeled activity or affinity probes is highly desirable. Especially for in vivodetection of low abundant target proteins, otherwise difficult to analyse by standard blotting techniques, fluorescently labeled profiling probes are of high value. Here, a one-pot protocol for the synthesis of activated fluorescent labels (i.e.azide, alkynyl or NHS), based on the Ugi-4-component reaction (Ugi-4CR), is presented. As a result of the peptoidic structure formed, the fluorescent properties of the products are pH insensitive. Moreover, the applicability of these probes, as exemplified by the labeling of model protein BSA, will be discussed.
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