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Publications associées (32)

Recent progress in alkynylation with hypervalent iodine reagents

Jérôme Waser, Eliott Hugo Joran Le Du

Although alkynes are one of the smallest functional groups, they are among the most versatile building blocks for organic chemistry, with applications ranging from biochemistry to material sciences. Alkynylation reactions have traditionally relied on the u ...

Royal Society of Chemistry2023

Divergent Asymmetric Total Synthesis of (−)‐Voacafricines A and B

Qian Wang, Jieping Zhu, Rémi Julien Sylvain Andres

A divergent asymmetric total synthesis of voacafricines A and B, hexacyclic monoterpene indole alkaloids, has been accomplished featuring the following key steps: a)a catalyst-controlled asymmetric Pictet– Spengler reaction of 6-methoxytryptamine with a ch ...

Wiley-VCH Verlag GmbH2023

N-Terminal Selective C-H Azidation of Proline-Containing Peptides: a Platform for Late-Stage Diversification

Jérôme Waser, Raphaël Michel Henri Simonet-Davin, Emmanuelle Madeline Dominique Allouche

A methodology for the C-H azidation of N-terminal proline-containing peptides was developed employing only commercially available reagents. Peptides bearing a broad range of functionalities and containing up to 6 amino acids were selectively azidated at th ...

2022

Anticancer ruthenium(II) tris(pyrazolyl)methane complexes with bioactive co-ligands

Paul Joseph Dyson, Sarah Alexandra Pais Pereira

In comparison with Ru-II-arene compounds, the medicinal potential of homologous Ru-II-tpm compounds [tpm = tris(pyrazolyl)methane] is underexplored. Pyridine, 4-pyridinemethanol and four functionalized pyridines, synthesized from the esterification of 4-py ...

ROYAL SOC CHEMISTRY2022

Copper-Catalyzed Alkynylation of Hydrazides: An Easy Access to Functionalized Azadipeptides

Jérôme Waser, Eliott Hugo Joran Le Du, Julien Aymeric Borrel

We report a copper-catalyzed alkynylation of azadipeptides using ethynylbenziodoxolone (EBX) reagents. Nonsymmetrical ynehydrazides could be obtained in 25–97% yield using azaglycine derivatives as nucleophiles. The transformation is compatible with most f ...

2022

Direct Photoexcitation of Ethynylbenziodoxolones: An Alternative to Photocatalysis for Alkynylation Reactions**

Jérôme Waser, Franck Le Vaillant, Stephanie Grace Elizabeth Amos, Diana Cavalli

Ethynylbenziodoxolones (EBXs) are commonly used as radical traps in photocatalytic alkynylations. Herein, we report that aryl-substituted EBX reagents can be directly activated by visible light irradiation. They act as both oxidants and radical traps, alle ...

Wiley-VCH Verlag GmbH2021

Tosyloxybenziodoxolone: A Platform for Performing the Umpolung of Alkynes in One-Pot Transformations

Jérôme Waser, Julien Aymeric Borrel

Ethynylbenziodoxolones (EBXs) are commonly encountered reagents for the electrophilic alkynylation of nucleophiles. Herein, we report a one-pot, two-step process for EBX generation and their direct application in substrate functionalization. Our approach e ...

2021

Schiff base ligands derived from 1,2-bis(2 '-nitro-/amino-phenoxy)-3-R-benzene and 2-hydroxy-1-naphthaldehyde and their Cu/Zn(II) complexes: synthesis, characterization, X-ray structures and computational studies

Rosario Scopelliti

1,2-Bis(2'-nitrophenoxy)-3-R-benzenes {R = H (1), CH3 (2) and OCH3 (3)} have been prepared from the S-N-Ar reaction between 1-fluoro-2-nitrobenzene and 3-R-catechol (aromatic diol), and are then reduced to the corresponding diamines 1,2-bis(2'-aminophenoxy ...

ROYAL SOC CHEMISTRY2021

Selective Acceptorless Dehydrogenation of Primary Amines to Imines by Core-Shell Cobalt Nanoparticles

Paul Joseph Dyson, Zhaofu Fei, Matthias Beller, Xinjiang Cui

Core-shell nanocatalysts are attractive due to their versatility and stability. Here, we describe cobalt nanoparticles encapsulated within graphitic shells prepared via the pyrolysis of a cationic poly-ionic liquid (PIL) with a cobalt(II) chloride anion. T ...

Wiley-VCH Verlag GmbH2020

Reactivity and biological activity of N,N,S-Schiff-base rhodium pentamethylcyclopentadienyl complexes

Paul Joseph Dyson, Lucinda Kate Batchelor

Neutral piano-stool complexes of the general formula [(eta(5)-C5Me5)Rh(L-OR)] (R = Me, 1; R = Et, 2; R = Pe(i), 3) have been prepared in alcohols (methanol, 1; ethanol, 2; isopropanol, 3) from the Schiff-base 5-methyl-4-{(pyridin-2-ylmethylene)amino}-4H-1, ...

ELSEVIER SCIENCE SA2020

Carbon Dioxide Reduction by Multimetallic Uranium(IV) Complexes Supported by Redox-Active Schiff Base Ligands

Rosario Scopelliti, Marinella Mazzanti, Marta Falcone, Nadir Jori

The synthesis, structure, and reactivity with CO2 and CS2 of new U(IV) complexes with a redox-active Schiff base are reported. The reaction of UI3 with the heptadentate Schiff base ligand 2,2',2 ''-tris(salicylideneimino)-triethylamine (trensal) did not le ...

2020

Organocatalysts in C-N Bond Forming Reactions of Amines with CO2

Martin Hulla

The thesis describes a simple approach for N-formylation of amines with CO2 and hydrosilane reducing agents, the use of organic salts as N-formylation catalysts, their physical properties required for high catalytic activity and their role in the catalytic ...

EPFL2019

Alkynylation of radicals: spotlight on the "Third Way" to transfer triple bonds

Jérôme Waser, Franck Le Vaillant

The alkynylation of radical intermediates has been known since a long time, but had not been broadly applied in synthetic chemistry, in contrast to the alkynylation of either electrophiles or nucleophiles. In the last decade however, it has been intensivel ...

2019

Photoredox-Catalyzed Decarboxylation for the Transfer of Alkynes and Nitriles Using Hypervalent Iodine Reagents

Franck Le Vaillant

Aliphatic alkynes and nitriles are privileged motifs in organic chemistry. Therefore, alkynes and nitriles have played a central role for the exploration and development of novel strategies to forge C-C bonds in efficient manner. They are broadly used as v ...

EPFL2019

Ethynylbenziodazolones (EBZ) as Electrophilic Alkynylation Reagents for the Highly Enantioselective Copper-Catalyzed Oxyalkynylation of Diazo Compounds

Rosario Scopelliti, Jérôme Waser, Lionel Schouwey, Farzaneh Fadaei Tirani, Durga Prasada Rao Hari, Verity Barber

Ethynylbenziodoxol(on)e (EBX) cyclic hypervalent iodine reagents are now established reagents for the alkynylation of radicals and nucleophiles, yet they present limited possibilities for further structure and reactivity modification. Herein, the first syn ...

2019

Kinetics and mechanisms of nitrate and ammonium formation during ozonation of dissolved organic nitrogen

Urs von Gunten, Glen Andrew De Vera

Dissolved organic nitrogen (DON) is an emerging concern in oxidative water treatment because it exerts oxidant demand and may form nitrogenous oxidation/disinfection by-products. In this study, we investigated the reactions of ozone with DON with a special ...

Elsevier2017

Dearomatization of electron poor six-membered N-heterocycles through [3+2] annulation with aminocyclopropanes

Jérôme Waser, Shyamal Chakrabarty, Johannes Preindl

Many abundant and highly bioactive natural alkaloids contain an indolizidine skeleton. A simple, high yielding method to synthesize this scaffold from N-heterocycles was developed. A wide range of pyridines, quinolines and isoquinolines reacted with donor- ...

2017

Stereoselective synthesis of alkenes via base-metal-catalyzed addition reactions to alkynes and activation of hydrogen peroxide and carbon dioxide by iron complexes

Fedor Zhurkin

Alkene functionality can be found in the majority of natural products, drugs, catalysts and organic materials. Therefore, methods of C-C double bond formation constitute a cornerstone of organic synthesis. Selective formation of either (Z)- or (E)-isomer i ...

EPFL2017

Organocatalytic Nucleophilic Addition of Hydrazones to Imines: Synthesis of Enantioenriched Vicinal Diamines

Qian Wang, Jieping Zhu, Yang Wang

In the presence of a catalytic amount of chiral phosphoric acid, nucleophilic addition of N-monosubstituted hydrazones to N-Boc imines affords differentially protected vicinal diamines in the form of b-amino N,N’-dialkyldiazenes in excellent yields with hi ...

Wiley-Blackwell2017

α-Oxo-Ketenimines from Isocyanides and α-Haloketones: Synthesis and Divergent Reactivity

Qian Wang, Jieping Zhu, Mathias Mamboury

The palladium-catalyzed reaction of a-haloketones with isocyanides afforded -oxo-ketenimines through alpha-hydride elimination of the beta-oxo-imidoyl palladium intermediates. Reaction of these relatively stable alpha-oxo ketenimines with nucleophiles suc ...

Wiley-Blackwell2017

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