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81.
Andreas Müller‐Schiffmann Julia Mrz‐Berberich Aksana Andreyeva Raik Rnicke Dirk Bartnik Oleksandr Brener Janine Kutzsche Anselm H. C. Horn Marco Hellmert Jolanta Polkowska Kurt Gottmann Klaus G. Reymann S. Aileen Funke Luitgart Nagel‐Steger Christine Moriscot Guy Schoehn Heinrich Sticht Dieter Willbold Thomas Schrader Carsten Korth 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2010,122(46):8925-8928
82.
[reaction: see text] Ruthenium alkylidene complexes 1-3 mediate hydrosilylation of alkynes with silanes. When triethoxy- or triphenylsilanes are used as silylating agents, the reaction affords alpha-substituted vinylsilanes as major products. 相似文献
83.
[structure: see text] A sequence of chemoselective cross-metathesis reactions and enantioselective allyltitanations of aldehydes has been used to prepare the C1-C13, C15-C26, and C27-C40 fragments of tetrafibricin. 相似文献
84.
An enantioselective synthesis of the piperidine alkaloids (+)-sedamine and (-)-prosophylline is reported. The synthesis of (+)-sedamine has been achieved in 12 steps with an overall yield of 20% from benzaldehyde, and (-)-prosophylline was obtained in 15 steps with an overall yield of 9.2%, starting from D-glyceraldehyde acetonide 14. The key steps are enantioselective allyltitanation reactions and ring-closing or cross-metathesis reactions. 相似文献
85.
Alexandre Le FlohicChristophe Meyer Janine Cossy Jean-Roger Desmurs 《Tetrahedron letters》2003,44(47):8577-8580
Various substituted unsaturated [1,2]oxazines have been synthesized by using a [2,3]- or a [3,3]-sigmatropic rearrangement and a ring-closing metathesis reaction as key steps. 相似文献
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90.
Christoph Batz‐Sohn 《Particle & Particle Systems Characterization》2003,20(6):370-378
Fumed oxides produced in gas‐phase processes, such as silicas and aluminum oxide, consist of a cluster of aggregated primary particles. The aggregate size of these particles is an important variable in many applications. However, current procedures for measuring particle sizes all assume that the particles have a spherical shape and are thus not truly capable of determining aggregate size. The results of such particle size measurements are consequently called “equivalent spherical diameter” (ESD), but these results vary from method to method. This publication shows that it is feasible to use the number of primary particles per aggregate, rather than the ESD, as a measure for the particle size of clusters of this type. The method is based on dynamic light scattering (photon correlation spectroscopy, PCS), which has proven itself in the analysis of fumed oxides. A numerical simulation based on random, computer‐generated model aggregates is used to modify the well‐known Stokes‐Einstein equation so that the number of primary particles can be determined. 相似文献