An efficient and simple method for the preparation of symmetrical disiloxanes from hydrosilanes by Lewis acid-catalyzed air oxidation
摘要:
Symmetrical disiloxanes were prepared in high yields by air oxidation of mono, di, and trihydrosilanes under Lewis acid catalysis. (c) 2009 Elsevier Ltd. All rights reserved.
Reactivity of a Titanocene Pendant Si–H Group toward Alcohols. Unexpected Formation of Siloxanes from the Reaction of Hydrosilanes and Ph<sub>3</sub>COH Catalyzed by B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>
hydrosilane. The different hydrosilane reactivity toward Ph3COH in comparison with other alcohols can be attributed to the easy generation of the borate salt [Ph3C]+[(C6F5)3B(μ-OH)B(C6F5)3]− (5) under catalytic conditions. The intramolecular Si–H and Ti–Cl exchange in 1 is catalyzed by B(C6F5)3 in the presence of no alcohol. This process affords presumably a transient titanocene hydrido chloride, which
An Efficient Catalytic Approach for the Synthesis of Unsymmetrical Siloxanes
作者:Grzegorz Hreczycho
DOI:10.1002/ejic.201402904
日期:2015.1
expanding the variety of catalytic methods for siloxane bond formation is explored. Alkoxysilanes react with methylallylsilanes in the presence of scandium(III) trifluoromethanesulfonate to yield disiloxanes and isobutene. The reaction proceeds through one-pot hydrolysis/O-silylation of alkoxysilanes with allylsilanes (via silanol intermediates) under mild conditions. Unsaturated siloxane products are used
A new selective approach to unsymmetrical siloxanes and germasiloxanes via O-metalation of silanols with 2-methylallylsilanes and 2-methylallylgermanes
A scandium(III) trifluoromethanesulfonate-catalyzed O-metalation of silanols with 2-methylallylsilanes and 2-methylallylgermanes leading to siloxane or germasiloxane bond formation under mild conditions with evolution of isobutylene is described.
Hydroxyapatite-supported goldnanoparticles (AuHAP) can act as highlyefficient and reusable catalysts for the oxidation of diverse silanes into silanols in water; this is the first catalytic methodology for the selective synthesis of aliphatic silanols using water under organic-solvent-free conditions.
This application relates to novel compounds of formula I (and their pharmaceutically acceptable salts), as defined herein, processes and intermediates for their preparation, pharmaceutical formulations comprising the novel compounds of formula I, and the use of the compounds of formula I as thrombin inhibitors.