- Bi- and tridentate silicon-based acceptor molecules
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Triethynylphenylsilane (1), trivinylphenylsilane (2), diethynyldiphenylsilane (3) and diphenyldivinylsilane (4) were reacted with chlorodimethylsilane yielding the corresponding hydrosilylation products. To increase their Lewis acidity, the Si-Cl functions were directly transferred into Si-C6F5 units by salt elimination reactions leading to the (semi-) flexible molecules 5-8 bearing two or three Lewis-acidic sidearms. With the aim of providing host-guest complexes, the air-stable and readily soluble compounds 5-8 were converted with N- and O-Lewis bases of different size and geometry. In all cases, NMR spectroscopic investigations reveal no formation of Lewis acid-base complexes. X-ray diffraction experiments of host compounds 5-7 show intermolecular aryl perfluoroaryl interactions of dispersion nature in the solid state. By hydrosilylation of 1 with trichlorosilane the more Lewisacidic all-trans-tris[(trichlorosilyl)vinyl]phenylsilane (9) was obtained. Its Lewis acidity was further increased by fluorination to yield all-trans-tris[(trifluorosilyl)vinyl] phenylsilane (10); the conversion with nitrogen containing Lewis bases ends up in the formation of insoluble precipitates.
- Horstmann, Jan,Lamm, Jan-Hendrik,Strothmann, Till,Neumann, Beate,Stammler, Hans-Georg,Mitzel, Norbert W.
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- A Two-Component Alkyne Metathesis Catalyst System with an Improved Substrate Scope and Functional Group Tolerance: Development and Applications to Natural Product Synthesis
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Although molybdenum alkylidyne complexes such as 1 endowed with triarylsilanolate ligands are excellent catalysts for alkyne metathesis, they can encounter limitations when (multiple) protic sites are present in a given substrate and/or when forcing conditions are necessary. In such cases, a catalyst formed in situ upon mixing of the trisamidomolybenum alkylidyne complex 3 and the readily available trisilanol derivatives 8 or 11 shows significantly better performance. This two-component system worked well for a series of model compounds comprising primary, secondary or phenolic -OH groups, as well as for a set of challenging (bis)propargylic substrates. Its remarkable efficiency is also evident from applications to the total syntheses of manshurolide, a highly strained sesquiterpene lactone with kinase inhibitory activity, and the structurally demanding immunosuppressive cyclodiyne ivorenolide A; in either case, the standard catalyst 1 largely failed to effect the critical macrocyclization, whereas the two-component system was fully operative. A study directed toward the quinolizidine alkaloid lythrancepine I features yet another instructive example, in that a triyne substrate was metathesized with the help of 3/11 such that two of the triple bonds participated in ring closure, while the third one passed uncompromised. As a spin-off of this project, a much improved ruthenium catalyst for the redox isomerization of propargyl alcohols to the corresponding enones was developed.
- Schaubach, Sebastian,Gebauer, Konrad,Ungeheuer, Felix,Hoffmeister, Laura,Ilg, Marina K.,Wirtz, Conny,Fürstner, Alois
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supporting information
p. 8494 - 8507
(2016/07/11)
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- NOVEL COMPOUND AND ORGANIC LIGHT-EMITTING DEVICE INCLUDING THE SAME
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Compounds represented by Formula 1 and organic light-emitting devices including an organic layer including the compounds are disclosed.
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Paragraph 0162; 0163
(2013/07/19)
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