178625-97-3Relevant academic research and scientific papers
Catalytic Carbocation Generation Enabled by the Mesolytic Cleavage of Alkoxyamine Radical Cations
Zhu, Qilei,Gentry, Emily C.,Knowles, Robert R.
, p. 9969 - 9973 (2016/08/16)
A new catalytic method is described to access carbocation intermediates via the mesolytic cleavage of alkoxyamine radical cations. In this process, electron transfer between an excited state oxidant and a TEMPO-derived alkoxyamine substrate gives rise to a radical cation with a remarkably weak C?O bond. Spontaneous scission results in the formation of the stable nitroxyl radical TEMPO.as well as a reactive carbocation intermediate that can be intercepted by a wide range of nucleophiles. Notably, this process occurs under neutral conditions and at comparatively mild potentials, enabling catalytic cation generation in the presence of both acid sensitive and easily oxidized nucleophilic partners.
Preparation of bifunctional mesoporous silica nanoparticles by orthogonal click reactions and their application in cooperative catalysis
Dickschat, Arne T.,Behrends, Frederik,Bühner, Martin,Ren, Jinjun,Wei?, Mark,Eckert, Hellmut,Studer, Armido
, p. 16689 - 16697 (2013/03/14)
The synthesis of bifunctional mesoporous silica nanoparticles is described. Two chemically orthogonal functionalities are incorporated into mesoporous silica by co-condensation of tetraethoxysilane with two orthogonally functionalized triethoxyalkylsilanes. Post-functionalization is achieved by orthogonal surface chemistry. A thiol-ene reaction, Cu-catalyzed 1,3-dipolar alkyne/azide cycloaddition, and a radical nitroxide exchange reaction are used as orthogonal processes to install two functionalities at the surface that differ in reactivity. Preparation of mesoporous silica nanoparticles bearing acidic and basic sites by this approach is discussed. Particles are analyzed by solid state NMR spectroscopy, elemental analysis, infrared-spectroscopy, and scanning electron microscopy. As a first application, these particles are successfully used as cooperative catalysts in the Henry reaction. Cooperative clicking: Bifunctional mesoporous silica particles were synthesized by orthogonal surface chemistry. A thiol-ene reaction, a copper-catalyzed 1,3-dipolar cycloaddition and a radical nitroxide exchange reaction were used as orthogonal processes for the introduction of the acid and base functionalities (see scheme). Catalytic activities of these bifunctionalized inorganic/organic hybrid materials were studied on the Henry reaction. Copyright
Aggregation behaviour of peptide-polymer conjugates containing linear peptide backbones and multiple polymer side chains prepared by nitroxide-mediated radical polymerization
Moeller, Michael,Hentschel, Carsten,Chi, Lifeng,Studer, Armido
, p. 2403 - 2412 (2011/05/14)
A series of peptides with an alternating sequence of alkoxyamine conjugated lysine and glycine residues were synthesized by classical solution phase peptide coupling. The resulting peptides containing up to eight alkoxyamine moieties were used as initiato
Immobilization of oligostyrene-prolinol conjugates into polystyrene via electrospinning and applications of these fibers in catalysis
Roeben, Caren,Stasiak, Michael,Janza, Birgit,Greiner, Andreas,Wendorff, Joachim H.,Studer, Armido
scheme or table, p. 2163 - 2168 (2009/04/06)
This paper reports the synthesis of prolinol-oligostytrene conjugates and their immobilization into a polystyrene matrix by using the electrospinning process. Via this approach fibers with a large surface area (fiber diameter of 1.2 μm) containing the pro
