@article{SchneiderBroseRalletal.2016, author = {Schneider, Florian D. and Brose, Ulrich and Rall, Bj{\"o}rn C. and Guill, Christian}, title = {Animal diversity and ecosystem functioning in dynamic food webs}, series = {Nature Communications}, volume = {7}, journal = {Nature Communications}, publisher = {Nature Publ. Group}, address = {London}, issn = {2041-1723}, doi = {10.1038/ncomms12718}, pages = {3129 -- 3138}, year = {2016}, abstract = {Species diversity is changing globally and locally, but the complexity of ecological communities hampers a general understanding of the consequences of animal species loss on ecosystem functioning. High animal diversity increases complementarity of herbivores but also increases feeding rates within the consumer guild. Depending on the balance of these counteracting mechanisms, species-rich animal communities may put plants under top-down control or may release them from grazing pressure. Using a dynamic food-web model with body-mass constraints, we simulate ecosystem functions of 20,000 communities of varying animal diversity. We show that diverse animal communities accumulate more biomass and are more exploitative on plants, despite their higher rates of intra-guild predation. However, they do not reduce plant biomass because the communities are composed of larger, and thus energetically more efficient, plant and animal species. This plasticity of community body-size structure reconciles the debate on the consequences of animal species loss for primary productivity.}, language = {en} } @article{Schneider2016, author = {Schneider, Birgit}, title = {Burning worlds of cartography: a critical approach to climate cosmograms of the Anthropocene}, series = {Geo : geography and environment}, volume = {3}, journal = {Geo : geography and environment}, publisher = {Wiley}, address = {Hoboken}, issn = {2054-4049}, doi = {10.1002/geo2.27}, pages = {15}, year = {2016}, abstract = {Climate science today makes use of a variety of red globes to explore and communicate findings. These transform the iconography which informs this image: the idealised, even mythical vision of the blue, vulnerable and perfect marble is impaired by the application of the colours yellow and red. Since only predictions that employ a lot of red seem to exist, spectators are confronted with the message that the future Earth that might turn out as envisaged here is undesirable. Here intuitively powerful narrations of the end of the world may connect. By employing methods of art history and visual analysis, and building on examples from current Intergovernmental Panel on Climate Change reports and future scenario maps, this article explores how burning world images bear - intentionally or not - elements of horror and shock. My question explored here is as follows: should 'burning world' images be understood as a new and powerful cosmology?}, language = {en} } @incollection{Schneider2016, author = {Schneider, Birgit}, title = {Der "Totaleindruck einer Gegend" Alexander von Humboldts synoptische Visualisierunge des Klimas}, series = {Horizonte der Humboldt-Forschung}, booktitle = {Horizonte der Humboldt-Forschung}, publisher = {Georg Olms Verlag}, address = {Hildesheim}, pages = {53 -- 78}, year = {2016}, language = {de} } @article{SchneiderWetterichSchirrmeisteretal.2016, author = {Schneider, Andrea and Wetterich, Sebastian and Schirrmeister, Lutz and Herzschuh, Ulrike and Meyer, Hanno and Pestryakova, Luidmila Agafyevna}, title = {Freshwater ostracods (Crustacea) and environmental variability of polygon ponds in the tundra of the Indigirka Lowland, north-east Siberia}, series = {Polar research : a Norwegian journal of Polar research}, volume = {35}, journal = {Polar research : a Norwegian journal of Polar research}, publisher = {Society of Exploration Geophysicists}, address = {Abingdon}, issn = {0800-0395}, doi = {10.3402/polar.v35.25225}, pages = {22}, year = {2016}, abstract = {Freshwater ostracods (Crustacea, Ostracoda) are valuable biological indicators. In Arctic environments, their habitat conditions are barely known and the abundance and diversity of ostracods is documented only in scattered records with incomplete ecological characterization. To determine the taxonomic range of ostracod assemblages and their habitat conditions in polygon ponds in the Indigirka Lowland, north-east Siberia, we collected more than 100 living ostracod individuals per site with a plankton net (mesh size 65 mm) and an exhaustor system from 27 water bodies and studied them in the context of substrate and hydrochemical data. During the summer of 2011, a single pond site and its ostracod population was selected for special study. This first record of the ostracod fauna in the Indigirka Lowland comprises eight species and three additional taxa. Fabaeformiscandona krochini and F. groenlandica were documented for the first time in continental Siberia. Repeated sampling of a low-centre polygon pond yielded insights into the population dynamics of F. pedata. We identified air temperature and precipitation as the main external drivers of water temperatures, water levels, ion concentrations and water stable isotope composition on diurnal and seasonal scales.}, language = {en} } @article{SchneidervanSchaikZangerleetal.2016, author = {Schneider, A. -K. and van Schaik, L. and Zangerle, A. and Eccard, Jana and Schroeder, B.}, title = {Which abiotic filters shape earthworm distribution patterns at the catchment scale?}, series = {European journal of soil science}, volume = {67}, journal = {European journal of soil science}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {1351-0754}, doi = {10.1111/ejss.12346}, pages = {431 -- 442}, year = {2016}, abstract = {Earthworms affect various soil ecosystem processes in their role as ecosystem engineers. The spatial distribution of earthworms determines the spatial distribution of their functional effects. In particular, earthworm-induced macropore networks may act as preferential flow pathways. In this research we aimed to determine earthworm distributions at the catchment scale with species distribution models (SDMs). We used land-use types, temporally invariant topography-related variables and plot-scale soil characteristics such as pH and organic matter content. We used data from spring 2013 to estimate probability distributions of the occurrence of ten earthworm species. To assess the robustness of these models, we tested temporal transferability by evaluating the accuracy of predictions from the models derived for the spring data with the predictions from data of two other field surveys in autumn 2012 and 2013. In addition, we compared the performance of SDMs based (i) on temporally varying plot-scale predictor variables with (ii) those based on temporally invariant catchment-scale predictors. Models based on catchment-scale predictors, especially land use and slope, experience a small loss of predictive performance only compared with plot-scale SDMs but have greater temporal transferability. Earthworm distribution maps derived from this kind of SDM are a prerequisite for understanding the spatial distribution patterns of functional effects related to earthworms.}, language = {en} } @article{Schmiegel2016, author = {Schmiegel, Tobias}, title = {Diskussionsbericht zum Vortrag von Prof. Dr. Ulrich Torggler LL.M. (Comell), (Universit{\"a}t Wien) "Psychologie der Massen - Neue Herausforderungen zur Einhegung von Fanverhalten im Profisport"}, series = {Aktuelle Rechtsfragen im Profifußball : psychologische Faktoren und rechtliche Gestaltung}, journal = {Aktuelle Rechtsfragen im Profifußball : psychologische Faktoren und rechtliche Gestaltung}, publisher = {Nomos}, address = {Bade-Baden}, isbn = {978-3-8487-2326-3}, pages = {181 -- 186}, year = {2016}, language = {de} } @article{SchmiedelArayaBortolottoetal.2016, author = {Schmiedel, Ute and Araya, Yoseph and Bortolotto, Maria Ieda and Boeckenhoff, Linda and Hallwachs, Winnie and Janzen, Daniel and Kolipaka, Shekhar S. and Novotny, Vojtech and Palm, Matilda and Parfondry, Marc and Smanis, Athanasios and Toko, Pagi}, title = {Contributions of paraecologists and parataxonomists to research, conservation, and social development}, series = {Conservation biology : the journal of the Society for Conservation Biology}, volume = {30}, journal = {Conservation biology : the journal of the Society for Conservation Biology}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0888-8892}, doi = {10.1111/cobi.12661}, pages = {506 -- 519}, year = {2016}, abstract = {Citizen science has been gaining momentum in the United States and Europe, where citizens are literate and often interested in science. However, in developing countries, which have a dire need for environmental data, such programs are slow to emerge, despite the large and untapped human resources in close proximity to areas of high biodiversity and poorly known floras and faunas. Thus, we propose that the parataxonomist and paraecologist approach, which originates from citizen-based science, is well suited to rural areas in developing countries. Being a paraecologist or a parataxonomist is a vocation and entails full-time employment underpinned by extensive training, whereas citizen science involves the temporary engagement of volunteers. Both approaches have their merits depending on the context and objectives of the research. We examined 4 ongoing paraecologist or parataxonomist programs in Costa Rica, India, Papua New Guinea, and southern Africa and compared their origins, long-term objectives, implementation strategies, activities, key challenges, achievements, and implications for resident communities. The programs supported ongoing research on biodiversity assessment, monitoring, and management, and participants engaged in non-academic capacity development in these fields. The programs in Southern Africa related to specific projects, whereas the programs in Costa Rica, India, and Papua New Guinea were designed for the long term, provided sufficient funding was available. The main focus of the paraecologists' and parataxonomists' activities ranged from collection and processing of specimens (Costa Rica and Papua New Guinea) or of socioeconomic and natural science data (India and Southern Africa) to communication between scientists and residents (India and Southern Africa). As members of both the local land user and research communities, paraecologists and parataxonomists can greatly improve the flow of biodiversity information to all users, from local stakeholders to international academia.}, language = {en} } @article{SchmiedchenLongardtLouietal.2016, author = {Schmiedchen, Bettina and Longardt, Ann Carolin and Loui, Andrea and Buehrer, Christoph and Raila, Jens and Schweigert, Florian J.}, title = {Effect of vitamin A supplementation on the urinary retinol excretion in very low birth weight infants}, series = {European journal of pediatrics : official organ of the Belgian Pediatric Association}, volume = {175}, journal = {European journal of pediatrics : official organ of the Belgian Pediatric Association}, publisher = {Springer}, address = {New York}, issn = {0340-6199}, doi = {10.1007/s00431-015-2647-9}, pages = {365 -- 372}, year = {2016}, abstract = {Despite high-dose vitamin A supplementation of very low birth weight infants (VLBW, <1500 g), their vitamin A status does not improve substantially. Unknown is the impact of urinary retinol excretion on the serum retinol concentration in these infants. Therefore, the effect of high-dose vitamin A supplementation on the urinary vitamin A excretion in VLBW infants was investigated. Sixty-three VLBW infants were treated with vitamin A (5000 IU intramuscular, 3 times/week for 4 weeks); 38 untreated infants were classified as control group. On days 3 and 28 of life, retinol, retinol-binding protein 4 (RBP4), glomerular filtration rate, proteinuria, and Tamm-Horsfall protein were quantified in urine. On day 3 of life, substantial retinol and RBP4 losses were found in both groups, which significantly decreased until day 28. Notwithstanding, the retinol excretion was higher (P<0.01) under vitamin A supplementation as compared to infants of the control group. On day 28 of life, the urinary retinol concentrations were predictive for serum retinol concentrations in the vitamin A treated (P<0.01), but not in the control group (P=0.570). Conclusion: High urinary retinol excretion may limit the vitamin A supplementation efficacy in VLBW infants. Advanced age and thus postnatal kidney maturation seems to be an important contributor in the prevention of urinary retinol losses.}, language = {en} } @book{Schmidt2016, author = {Schmidt, Thorsten Ingo}, title = {Finanzierungspflichten und Konnexit{\"a}tsprinzip}, series = {Recht der Steuern und der {\"o}ffentlichen Finanzordnung ; 10}, journal = {Recht der Steuern und der {\"o}ffentlichen Finanzordnung ; 10}, editor = {Gosch, Dietmar and Hufeld, Ulrich and Kirchhof, Gregor and Rust, Alexander and Schenke, Ralf and Tappe, Henning and Weitemeyer, Birgit}, publisher = {Nomos}, address = {Baden-Baden}, isbn = {978-3-8487-2822-0}, publisher = {Universit{\"a}t Potsdam}, pages = {86}, year = {2016}, abstract = {Die Finanzkrise der Kommunen beruht auch auf der {\"U}bertragung staatlicher Aufgaben ohne entsprechenden finanziellen Ausgleich. Davor sollen nun das grundgesetzliche Aufgaben{\"u}bertragungsverbot vom Bund auf die Kommunen und die landesverfassungsrechtlichen Konnexit{\"a}tsregeln beim Transfer vom Land auf die Kommunen sch{\"u}tzen. Zwar ist anerkannt, dass diese Vorschriften f{\"u}r Sachaufgaben gelten. Doch ist streitig, ob dies auch f{\"u}r die Auferlegung von Finanzierungspflichten zu gelten hat. Der Autor vergleicht die landesverfassungsrechtlichen Bestimmungen in ihrer Auslegung durch das jeweilige Landesverfassungsgericht und arbeitet unter besonderer Ber{\"u}cksichtigung der nordrhein-westf{\"a}lischen Rechtslage heraus, dass die {\"U}bertragungsvorschriften nicht umgangen werden d{\"u}rfen. {\"U}bertragung einer Sachaufgabe und Auferlegung einer Finanzierungspflicht sind funktionell gleichwertig und beide konnexit{\"a}tsrelevant. Der Autor ist Direktor des Kommunalwissenschaftlichen Instituts der Universit{\"a}t Potsdam.}, language = {de} } @book{Schmidt2016, author = {Schmidt, Thorsten Ingo}, title = {Das Mitverwaltungsmodell}, series = {Kommunalrechtliche Studien ; 3}, journal = {Kommunalrechtliche Studien ; 3}, editor = {Br{\"u}ning, Christoph and Schmidt, Thorsten Ingo}, publisher = {Nomos}, address = {Baden-Baden}, isbn = {978-3-8487-2797-1}, publisher = {Universit{\"a}t Potsdam}, pages = {165}, year = {2016}, abstract = {Demographischer Wandel einerseits und zunehmende Aufgaben andererseits erzwingen bei finanzieller Notlage kommunale Reformen. Vielfach antworten die Landesgesetzgeber auf diesen Reformbedarf mit immer gr{\"o}ßeren kommunalen Einheiten. Um dieser „Flucht in die Einheitsgemeinde" entgegenzuwirken, entwickelt der Verfasser das Mitverwaltungsmodell: Eine Gemeinde bleibt zwar rechtlich selbstst{\"a}ndig, bedient sich aber der hauptamtlichen Verwaltung einer anderen Gemeinde. Die M{\"o}glichkeit einer solchen {\"o}ffentlich-rechtlichen Gesch{\"a}ftsbesorgung wird unter Wahrung der Selbstverwaltungsgarantie beider Gemeinden entfaltet. Die notwendigen gesetzlichen Bestimmungen und vertraglichen Regelungen werden entworfen. Dieses Modell soll im Rahmen der Brandenburgischen Verwaltungsstrukturreform umgesetzt werden und kann auch anderen L{\"a}ndern als Vorbild dienen. Der Autor ist Direktor des Kommunalwissenschaftlichen Instituts der Universit{\"a}t Potsdam.}, language = {de} } @article{SchmidtSaxenhoferDrewesetal.2016, author = {Schmidt, Sabrina and Saxenhofer, Moritz and Drewes, Stephan and Schlegel, Mathias and Wanka, Konrad M. and Frank, Raphael and Klimpel, Sven and von Blanckenhagen, Felix and Maaz, Denny and Herden, Christiane and Freise, Jona and Wolf, Ronny and Stubbe, Michael and Borkenhagen, Peter and Ansorge, Hermann and Eccard, Jana and Lang, Johannes and Jourdain, Elsa and Jacob, Jens and Marianneau, Philippe and Heckel, Gerald and Ulrich, Rainer G{\"u}nter}, title = {High genetic structuring of Tula hantavirus}, series = {Archives of virology}, volume = {161}, journal = {Archives of virology}, publisher = {Springer}, address = {Wien}, issn = {0304-8608}, doi = {10.1007/s00705-016-2762-6}, pages = {1135 -- 1149}, year = {2016}, abstract = {Tula virus (TULV) is a vole-associated hantavirus with low or no pathogenicity to humans. In the present study, 686 common voles (Microtus arvalis), 249 field voles (Microtus agrestis) and 30 water voles (Arvicola spec.) were collected at 79 sites in Germany, Luxembourg and France and screened by RT-PCR and TULV-IgG ELISA. TULV-specific RNA and/or antibodies were detected at 43 of the sites, demonstrating a geographically widespread distribution of the virus in the studied area. The TULV prevalence in common voles (16.7 \%) was higher than that in field voles (9.2 \%) and water voles (10.0 \%). Time series data at ten trapping sites showed evidence of a lasting presence of TULV RNA within common vole populations for up to 34 months, although usually at low prevalence. Phylogenetic analysis demonstrated a strong genetic structuring of TULV sequences according to geography and independent of the rodent species, confirming the common vole as the preferential host, with spillover infections to co-occurring field and water voles. TULV phylogenetic clades showed a general association with evolutionary lineages in the common vole as assessed by mitochondrial DNA sequences on a large geographical scale, but with local-scale discrepancies in the contact areas.}, language = {en} } @article{SchmidtWalzJonesetal.2016, author = {Schmidt, Katja and Walz, Ariane and Jones, Isobel and Metzger, Marc J.}, title = {The Sociocultural Value of Upland Regions in the Vicinity of Cities in Comparison With Urban Green Spaces}, series = {Mountain research and development}, volume = {36}, journal = {Mountain research and development}, publisher = {American Geophysical Union}, address = {Lawrence}, issn = {0276-4741}, doi = {10.1659/MRD-JOURNAL-D-16-00044.1}, pages = {465 -- 474}, year = {2016}, language = {en} } @misc{SchmidtSachseWalz2016, author = {Schmidt, Katja and Sachse, Rene and Walz, Ariane}, title = {Current role of social benefits in ecosystem service assessments}, series = {Landscape and urban planning : an international journal of landscape ecology, planning and design}, volume = {149}, journal = {Landscape and urban planning : an international journal of landscape ecology, planning and design}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0169-2046}, doi = {10.1016/j.landurbplan.2016.01.005}, pages = {49 -- 64}, year = {2016}, abstract = {Ecosystem services have a significant impact on human wellbeing. While ecosystem services are frequently represented by monetary values, social values and underlying social benefits remain underexplored. The purpose of this study is to assess whether and how social benefits have been explicitly addressed within socio-economic and socio-cultural ecosystem services research, ultimately allowing a better understanding between ecosystem services and human well-being. In this paper, we reviewed 115 international primary valuation studies and tested four hypotheses associated to the identification of social benefits of ecosystem services using logistic regressions. Tested hypotheses were that (1) social benefits are mostly derived in studies that assess cultural ecosystem services as opposed to other ecosystem service types, (2) there is a pattern of social benefits and certain cultural ecosystem services assessed simultaneously, (3) monetary valuation techniques go beyond expressing monetary values and convey social benefits, and (4) directly addressing stakeholde\&\#341;s views the consideration of social benefits in ecosystem service assessments. Our analysis revealed that (1) a variety of social benefits are valued in studies that assess either of the four ecosystem service types, (2) certain social benefits are likely to co-occur in combination with certain cultural ecosystem services, (3) of the studies that employed monetary valuation techniques, simulated market approaches overlapped most frequently with the assessment of social benefits and (4) studies that directly incorporate stakeholder's views were more likely to also assess social benefits.}, language = {en} } @article{SchmidtRoedigerGruneretal.2016, author = {Schmidt, Carsten and Roediger, Stefan and Gruner, Melanie and Moncsek, Anja and Stohwasser, Ralf and Hanack, Katja and Schierack, Peter and Schroeder, Christian}, title = {Multiplex localization of sequential peptide epitopes by use of a planar microbead chip}, series = {Analytica chimica acta : an international journal devoted to all branches of analytical chemistry}, volume = {908}, journal = {Analytica chimica acta : an international journal devoted to all branches of analytical chemistry}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0003-2670}, doi = {10.1016/j.aca.2015.12.030}, pages = {150 -- 160}, year = {2016}, abstract = {Epitope mapping is crucial for the characterization of protein-specific antibodies. Commonly, small overlapping peptides are chemically synthesized and immobilized to determine the specific peptide sequence. In this study, we report the use of a fast and inexpensive planar microbead chip for epitope mapping. We developed a generic strategy for expressing recombinant peptide libraries instead of using expensive synthetic peptide libraries. A biotin moiety was introduced in vivo at a defined peptide position using biotin ligase. Peptides in crude Escherichia coli lysate were coupled onto streptavidin-coated microbeads by incubation, thereby avoiding tedious purification procedures. For read-out we used a multiplex planar microbead chip with size- and fluorescence-encoded microbead populations. For epitope mapping, up to 18 populations of peptide-loaded microbeads (at least 20 microbeads per peptide) displaying the primary sequence of a protein were analyzed simultaneously. If an epitope was recognized by an antibody, a secondary fluorescence-labeled antibody generated a signal that was quantified, and the mean value of all microbeads in the population was calculated. We mapped the epitopes for rabbit anti-PA28 gamma (proteasome activator 28 gamma) polyclonal serum, for a murine monoclonal antibody against PA28 gamma, and for a murine monoclonal antibody against the hamster polyoma virus major capsid protein VP1 as models. In each case, the identification of one distinct peptide sequence out of up to 18 sequences was possible. Using this approach, an epitope can be mapped multiparametrically within three weeks. (C) 2016 Elsevier B.V. All rights reserved.}, language = {en} } @article{SchmidtLorenz2016, author = {Schmidt, Burkhard and Lorenz, Ulf}, title = {WavePacket}, series = {Computer physics communications : an international journal devoted to computational physics and computer programs in physics}, volume = {213}, journal = {Computer physics communications : an international journal devoted to computational physics and computer programs in physics}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0010-4655}, doi = {10.1016/j.cpc.2016.12.007}, pages = {223 -- 234}, year = {2016}, abstract = {WavePacket is an open-source program package for the numerical simulation of quantum-mechanical dynamics. It can be used to solve time-independent or time-dependent linear Schr{\"o}dinger and Liouville-von Neumann-equations in one or more dimensions. Also coupled equations can be treated, which allows to simulate molecular quantum dynamics beyond the Born-Oppenheimer approximation. Optionally accounting for the interaction with external electric fields within the semiclassical dipole approximation, WavePacket can be used to simulate experiments involving tailored light pulses in photo-induced physics or chemistry. The graphical capabilities allow visualization of quantum dynamics 'on the fly', including Wigner phase space representations. Being easy to use and highly versatile, WavePacket is well suited for the teaching of quantum mechanics as well as for research projects in atomic, molecular and optical physics or in physical or theoretical chemistry. The present Part I deals with the description of closed quantum systems in terms of Schr{\"o}dinger equations. The emphasis is on discrete variable representations for spatial discretization as well as various techniques for temporal discretization. The upcoming Part II will focus on open quantum systems and dimension reduction; it also describes the codes for optimal control of quantum dynamics. The present work introduces the MATLAB version of WavePacket 5.2.1 which is hosted at the Sourceforge platform, where extensive Wiki-documentation as well as worked-out demonstration examples can be found.}, language = {en} } @article{SchmidtZiemannPentzienetal.2016, author = {Schmidt, Birgit Angelika and Ziemann, Martin Andreas and Pentzien, Simone and Gabsch, Toralf and Koch, Werner and Kr{\"u}ger, J{\"o}rg}, title = {Technical analysis of a Central Asian wall painting detached from a Buddhist cave temple on the northern Silk Road}, series = {Studies in Conservation}, volume = {61}, journal = {Studies in Conservation}, publisher = {Routledge, Taylor \& Francis Group}, address = {Abingdon}, issn = {0039-3630}, doi = {10.1179/2047058414Y.0000000152}, pages = {113 -- 122}, year = {2016}, abstract = {A great number of Central Asian wall paintings, archeological materials, architectural fragments, and textiles, as well as painting fragments on silk and paper, make up the so called Turfan Collection at the Asian Art Museum in Berlin. The largest part of the collection comes from the Kucha region, a very important cultural center in the third to ninth centuries. Between 1902 and 1914, four German expeditions traveled along the northern Silk Road. During these expeditions, wall paintings were detached from their original settings in Buddhist cave complexes. This paper reports a technical study of a wall painting, existing in eight fragments, from the Buddhist cave no. 40 (Ritterhohle). Its original painted surface is soot blackened and largely illegible. Gruwedel, leader of the first and third expeditions, described the almost complete destruction of the rediscovered temple complex and evidence of fire damage. The aim of this case study is to identify the materials used for the wall paintings. Furthermore, soot deposits as well as materials from conservation interventions were of interest. Non-invasive analyses were preferred but a limited number of samples were taken to provide more precise information on the painting technique. By employing optical and scanning electron microscopy, energy dispersive X-ray spectroscopy, micro X-ray fluorescence spectroscopy, X-ray diffraction analysis, and Raman spectroscopy, a layer sequence of earthen render, a ground layer made of gypsum, and a paint layer containing a variety of inorganic pigments were identified.}, language = {en} } @article{SchmidtWolfEhlert2016, author = {Schmidt, Bernd and Wolf, Felix and Ehlert, Christopher}, title = {Systematic Investigation into the Matsuda-Heck Reaction of alpha-Methylene Lactones: How Conformational Constraints Direct the beta-H-Elimination Step}, series = {The journal of organic chemistry}, volume = {81}, journal = {The journal of organic chemistry}, publisher = {American Chemical Society}, address = {Washington}, issn = {0022-3263}, doi = {10.1021/acs.joc.6b02207}, pages = {11235 -- 11249}, year = {2016}, abstract = {alpha-Methylene-gamma-butyrolactone and alpha-methylene-gamma-valerolactone undergo Pd-catalyzed Matsuda-Heck couplings with arene diazonium salts to alpha-benzyl butenolides or pentenolides, respectively, or to alpha-benzylidene lactones. The observed regioselectivity is strongly ring size dependent, with six-membered rings giving exclusively alpha-benzyl pentenolides, whereas the five-membered alpha-methylene lactone reacts to mixtures of regioisomers with a high proportion of (E)-alpha-benzylidene-gamma-butyrolactones. DFT calculations suggest that the reasons for these differences are not thermodynamic but kinetic in nature. The relative energies of the conformers of the Pd sigma-complexes resulting from insertion into the Pd-aryl bond were correlated with the dihedral angles between Pd and endo-beta-H. This correlation revealed that in the case of the six-membered lactone an energetically favorable conformer adopts a nearly synperiplanar Pd/endo-beta-H arrangement, whereas for the analogous Pd sigma-complex of the five-membered lactone the smallest Pd/endo-beta-H dihedral angle is observed for a conformer with a comparatively high potential energy. The optimized conditions for Matsuda-Heck arylations of exo-methylene lactones were eventually applied to the synthesis of the natural product anemarcoumarin A.}, language = {en} } @article{SchmidtWolfBrunner2016, author = {Schmidt, Bernd and Wolf, Felix and Brunner, Heiko}, title = {Styrylsulfonates and -Sulfonamides through Pd-Catalysed Matsuda-Heck Reactions of Vinylsulfonic Acid Derivatives and Arenediazonium Salts}, series = {European journal of organic chemistry}, journal = {European journal of organic chemistry}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1434-193X}, doi = {10.1002/ejoc.201600469}, pages = {2972 -- 2982}, year = {2016}, abstract = {Arene diazonium salts undergo Matsuda-Heck reactions with vinylsulfonates and -sulfonamides to give styrylsulfonic acid derivatives in high to excellent yields and with high to excellent selectivities. By quantifying the evolution of nitrogen over time in a gas-meter apparatus, the reactivities of ethylvinylsulfonate and the benchmark olefin methyl acrylate were compared for an electron-rich and an -deficient arene diazonium salt. Tertiary sulfonamides react in Matsuda-Heck couplings with high conversions, but require long reaction times, which prevents the determination of kinetic data through the measurement of nitrogen evolution. Secondary sulfonamides were found to be unreactive. From these results, the following order of reactivity could be deduced: H2C=CHCO2Me > H2C=CHSO2OEt > H2C=CHSO2N(Me)Bn >> H2C=CHSO2NHBn. Through the Matsuda-Heck coupling of 5-indolyldiazonium salt and a tertiary vinylsulfonamide, the synthesis of the C-5-substituted indole part of the antimigraine drug naratriptan was accomplished in high yield.}, language = {en} } @article{SchmidtRiemer2016, author = {Schmidt, Bernd and Riemer, Martin}, title = {Microwave-Promoted Deprenylation: Prenyl Ether as a Thermolabile Phenol Protecting Group}, series = {Synthesis}, volume = {48}, journal = {Synthesis}, publisher = {Thieme}, address = {Stuttgart}, issn = {0039-7881}, doi = {10.1055/s-0035-1561366}, pages = {1399 -- 1406}, year = {2016}, abstract = {para-Substituted aryl prenyl ethers undergo a deprenylation reaction upon microwave irradiation. This offers the opportunity to use a prenyl ether as a thermolabile protecting group in the synthesis of natural products with a chromone structure, which proceeds via a tandem deprenylation/6-endo-cyclization sequence.}, language = {en} } @article{SchmidtRiemer2016, author = {Schmidt, Bernd and Riemer, Martin}, title = {Synthesis of Allyl- and Prenylcoumarins via Microwave-Promoted Tandem Claisen Rearrangement/Wittig Olefination}, series = {Synthesis}, volume = {48}, journal = {Synthesis}, publisher = {Thieme}, address = {Stuttgart}, issn = {0039-7881}, doi = {10.1055/s-0035-1560501}, pages = {141 -- 149}, year = {2016}, abstract = {Allyl, dimethylallyl, crotyl, and prenyl ethers of various aromatic ortho-hydroxy carbonyl compounds undergo a tandem sequence of Claisen rearrangement, carbonyl olefination, and cyclization upon microwave irradiation in the presence of a stabilized ylide. The products are multiply substituted 6- or 8-allylated or prenylated coumarins (2H-chromen-2-ones).}, language = {en} }