Publications by Gregor Kiefer | EPFL Graph Search

Divergent Asymmetric Synthesis of Polycyclic Compounds via Vinyl Triazenes

Kay Severin, Rosario Scopelliti, Gregor Kiefer, Florian Gérald Abela, Nicolai Cramer, David Kossler, Abdusalom Suleymanov

Vinyl triazenes were obtained by enantioselective [2+2] cycloaddition reactions of bicyclic alkenes with 1-alkynyl triazenes in the presence of a RuII catalyst with a chiral cyclopentadienyl ligand. These triazenes serve as unique vinyl cation surrogates. ...

Wiley-VCH Verlag GmbH2017

Preparation and medical use of triazenes

Kay Severin, Gregor Kiefer

The present invention relates to a novel method for preparing triazenes. Further, the invention relates to novel triazenes and the use of N2O for preparing a compound comprising a triazene group. Further, the invention relates to the use of the novel triaz ...

2015

Synthesis of Triazenes with Nitrous Oxide

Kay Severin, Rosario Scopelliti, Paul Joseph Dyson, Gregor Kiefer, Tina Riedel

Triazenes are valuable compounds in organic chemistry and numerous applications have been reported. Furthermore, triazenes have been investigated extensively as potential antitumor drugs. Here, we describe a new method for the synthesis of triazenes. The p ...

Wiley-Blackwell2015

Novel Applications of Nitrous Oxide and Transition Metals for C-C and C-N Bond Formation

Gregor Kiefer

This thesis describes novel methods for and investigations into C–C and C–N bond formation reactions. Chapter 1 gives a very brief overview of established strategies for the formation of new C–C bonds in organic synthesis. In chapter 2, a multi‐step one‐po ...

EPFL2015

1-Alkynyltriazenes as Functional Analogues of Ynamides

Kay Severin, Rosario Scopelliti, Jérôme Waser, Gregor Kiefer, Loïc Nicolas Jeanbourquin, Florian Gérald Abela, Sophie Lucie Racine, Daniele Perrotta

The chemical reactivity of 1-alkynyltriazenes has been investigated and is found to parallel the reactivity of ynamides. The similarity in reactivity of these two classes of compounds is demonstrated by addition reactions with acids, by cycloaddition react ...

Wiley-Blackwell2015

The Intricate Chemistry of Cobalt(II) Halides and Bis(diphenylphosphanyl)ethane

Kay Severin, Rosario Scopelliti, Heron Vrubel, Gregor Kiefer

Phosphane complexes of the putative formula [CoX2(dppe)] [X = Cl, Br, I; dppe = bis(diphenylphosphanyl)ethane] are frequently used catalyst precursors in cobalt-catalyzed reactions. Despite their widespread use, these complexes have not been structurally c ...

Wiley-Blackwell2013

Oxidative Coupling Reactions of Grignard Reagents with Nitrous Oxide

Kay Severin, Gregor Kiefer, Loïc Nicolas Jeanbourquin

Catalysis with laughing gas: N2O in combination with transition-metal catalysts allow the oxidative homo- and cross-coupling of Grignard reagents. The reactions can be performed under mild conditions despite the inert character of N2O. ...

Wiley-Blackwell2013

Ruthenium-Catalyzed Sequential Enyne Cross-Metathesis/ATRA Reactions

Kay Severin, Euro Solari, Jesus Ruiz, Gregor Kiefer

Sequential enyne cross-metathesis reactions of arylalkynes with ethylene followed by atom transfer radical addition (ATRA) with ethyl dichloroacetate or dichloroacetonitrile provide 1,5-dichloropent-2-ene derivatives. The second-generation Grubbs alkyliden ...

Wiley-Blackwell2012

RhCl3-Mediated Coupling Reactions of tert-Butyl Acetylene

Kay Severin, Rosario Scopelliti, Euro Solari, Barnali Dutta, Gregor Kiefer

RhCl3 is shown to mediate unusual coupling reactions of tert-butyl acetylene. When RhCl3(H2O)n was heated with four equivalents of tert-butyl acetylene in methanol, the dinuclear complex [{Rh(μ-Cl)(CH2tBu)(tBuC=CHCOCH2tBu)}2] (2) was isolated. A larger exc ...

Wiley-Blackwell2012

Atom-Transfer Radical Addition Reactions Catalyzed by RuCp* Complexes: A Mechanistic Study

Andrzej Sienkiewicz, Kay Severin, Katrin Anne Thommes, Katarzyna Pierzchala, Gregor Kiefer

Kinetic and spectroscopic analyses were performed to gain information about the mechanism of atom-transfer radical reactions catalyzed by the complexes [RuCl2Cp*(PPh3)] and [RuClCp*(PPh3)2] (Cp*=pentamethylcyclopentadienyl), in the presence and in the abse ...

2009

Olefin Cyclopropanation by a Sequential Atom-Transfer Radical Addition and Dechlorination in the Presence of a Ruthenium Catalyst

Kay Severin, Rosario Scopelliti, Katrin Anne Thommes, Gregor Kiefer

Wiley-VCH Verlag GmbH2009