Publications associées à Carbocation

Investigations about the Chemistry of Tetraarylethene- and Iridium-Based Luminophores

The work described in this thesis focuses on two classes of luminophores: tetraarylethene-based polymers and Ir(III) complexes with orthometalated ligands. Tetraarylethene-based polymers show aggregation-induced emission (AIE) and they are of interest for ...

EPFL2024

New Applications of 1,3,2-Diazaphospholenes in Catalysis

Johannes Klett

The constant urge to construct new molecules in an economical and sustainable fashion led to the development of numerous metal-catalyzed transformations. Organocatalysts consisting of abundant and more sustainable elements offer an elegant solution to over ...

EPFL2024

Development of Hetero-Vinylbenziodoxolone Reagents for Applications in Synthetic Methodology and Biomolecule Functionalization

Nina Declas

Among the numerous existing chemical motifs, alkenes, alkynes, enol ethers and enamides, with an unsaturated carbon-carbon bond, are versatile functional groups that are found in many natural products and bioactive compounds. They are widely used as valuab ...

EPFL2023

Semipinacol Rearrangement of Cyclopropenylcarbinols for the Synthesis of Highly Substituted Cyclopropanes

Jérôme Waser, Vladyslav Smyrnov

An electrophile-induced semipinacol rearrangement of cyclopropenylcarbinols is reported. This transformation gives access to various polyfunctionalized cyclopropanes under mild metal-free conditions. The scope of the reaction includes iodine, sulfur and se ...

2023

(4+3) Annulation of Donor-Acceptor Cyclopropanes and Azadienes: Highly Stereoselective Synthesis of Azepanones

Jérôme Waser, Stefano Nicolai

Azepanes are important seven-membered heterocycles, which are present in numerous natural and synthetic compounds. However, the development of convergent synthetic methods to access them remains challenging. Herein, we report the Lewis acid catalyzed (4+3) ...

Wiley-VCH Verlag GmbH2022

Tuning Napththalenediimide Cations for Incorporation into Ruddlesden–Popper-Type Hybrid Perovskites

Jacques-Edouard Moser, Kevin Sivula, Jun Ho Yum, Liang Yao, Etienne Christophe Socie, Simon Nussbaum

Layered hybrid organic−inorganic perovskite (LHOIP) materials constructed with low-band-gap chromophore-based organic spacer cations are anemerging class of materials that promise unique tunability of their optoelectronic properties. However, the large siz ...

2022

Catalytic Enantioselective Pictet–Spengler Reaction of α‐Ketoamides Catalyzed by a Single H‐Bond Donor Organocatalyst

Jieping Zhu, Qiang Wang, Rémi Julien Sylvain Andres

The asymmetric Pictet–Spengler reaction (PSR) with aldehydes is well known. However, PSR involving ketones as electrophilic partners is far-less developed. We report herein the first examples of catalytic enantioselective PSR of tryptamines with α-ketoamid ...

Wiley-VCH Verlag GmbH2022

Access to Vinyl Ethers and Ketones with Hypervalent Iodine Reagents as Oxy-Allyl Cation Synthetic Equivalents

Jérôme Waser, Nina Declas

We report an Umpolung strategy of enol ethers to generate oxy-allyl cation equivalents based on the use of hypervalent iodine reagents. Under mild basic conditions, the addition of nucleophiles to aryloxy-substituted vinylbenziodoxolone (VBX) reagents, eas ...

Wiley-VCH Verlag GmbH2020

Photocatalysis with organic dyes: facile access to reactive intermediates for synthesis

Jérôme Waser, Marion Marie-Agnès Garreau, Stephanie Grace Elizabeth Amos, Luca Buzzetti

Organic dyes have emerged as a reliable class of photoredox catalysts. Their great structural variety combined with the easy finetuning of their electronic properties has unlocked new possibilities for the generation of reactive intermediates. In this revi ...

2020

SET processes in Lewis acid–base reactions: the tritylation of N-heterocyclic carbenes

Rosario Scopelliti, Kay Severin, Farzaneh Fadaei Tirani, Andrzej Sienkiewicz, Cristian Pezzato, Zhaowen Dong

Reactions between N-heterocyclic carbenes (NHCs) and the trityl cation, [Ph3C]+, give covalent adducts of type [NHC–CPh3]+ and/or [NHC–C6H5–CPh2]+. EPR spectroscopy, UV-Vis analyses, and trapping experiments imply that adduct formation involves carbene rad ...

2020

"Doubly Orthogonal" Labeling of Peptides and Proteins

Jérôme Waser, Beat Fierz, Nora Guidotti, Raphaël Michel Henri Simonet-Davin, Romain Gaëtan Tessier

Herein, we report a cysteine bioconjugation methodology for the introduction of hypervalent iodine compounds onto biomolecules. Ethynylbenziodoxolones (EBXs) engage thiols in small organic molecules and cysteine-containing peptides and proteins in a fast a ...

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

Investigations of the Chemistry of 1-Alkynyltriazenes

Florian Gérald Abela

The chemistry of aromatic triazenes is well known, and has been explored for more than a century. These compounds have emerged as very useful intermediates, because of their unique reactivity. This functionality can notably be used to access many other fun ...

EPFL2018

Modelling of advanced three-ion ICRF heating and fast ion generation scheme for tokamaks and stellarators

Jonathan Graves, Laurent Villard, Wilfred Anthony Cooper, David Pfefferlé, Jonathan Marc Philippe Faustin, Samuel Lanthaler

Absorption of ion-cyclotron range of frequencies waves at the fundamental resonance is an efficient source of plasma heating and fast ion generation in tokamaks and stellarators. This heating method is planned to be exploited as a fast ion source in the We ...

2017

Superconductivity in semimetallic Bi3O2S3

Henrik Moodysson Rønnow, Lin Yang, Peter Babkevich, David Parker

Here we report a further investigation on the thermodynamic and transport properties, and an assessment of theoretical calculations, for the BiS2- layered Bi3O2S3 superconductor. The polycrystalline sample is synthesized with a superconducting transition t ...

American Physical Society2015

Homogenous catalytic hydrogenation of bicarbonate with water soluble aryl phosphine ligands

Paul Joseph Dyson, Gabor Laurenczy, Katerina Stefania Sordakis

The chemical transformation of CO2 and bicarbonates into useful products becomes increasingly impor- tant as the atmospheric CO2 level has reached 400 ppm. Here a small library of sulfonated aryl mono- phosphines and aryl diphosphines was tested as stabili ...

Elsevier2015

Cyclization and annulation reactions of nitrogen-substituted cyclopropanes and cyclobutanes

Jérôme Waser, Reto Frei, Fides Benfatti, Florian Patrick Marie Daniel De la Barre De Nanteuil, Filippo De Simone, Eloísa Sofía Serrano Robledo

Cyclization and annulation reactions initiated by ring-opening of small rings, especially cyclopropanes and cyclobutanes are now well-established in synthetic chemistry. Nevertheless, the potential of aminocyclopropanes and cyclobutanes, an important subcl ...

Royal Society of Chemistry2014

Direct Evaluation of the Hyperconjugative Interactions in 1,1,1-Trihaloethane (CH3CX3, X = F, Cl, and Br)

Anne-Clémence Corminboeuf, Zhenhua Chen

Following the computational strategy proposed by Mulliken in 1939 (J. Chem. Phys. 1939, 7 (5), 339-352), when the concept of hyperconjugation was coined, we evaluated the hyperconjugative stabilization energy in 1,1,1-trihaloethane using the block-localize ...

Amer Chemical Soc2014

Diester-Substituted Aminocyclopropanes: Synthesis and Use in [3+2]-Annulation Reactions

Jérôme Waser, Florian Patrick Marie Daniel De la Barre De Nanteuil, Eloísa Sofía Serrano Robledo

In this Letter, we describe the synthesis of new donor-acceptor substituted cyclopropanes bearing various imido groups and their use in [3+2]-annulation reactions. A sequence of palladium-catalyzed vinylation and rhodium-catalyzed cyclopropanation gave acc ...

Georg Thieme Verlag2014

Fast and Highly Chemoselective Alkynylation of Thiols with Hypervalent Iodine Reagents Enabled through a Low Energy Barrier Concerted Mechanism

Jérôme Waser, Matthew Wodrich, Reto Frei, Durga Prasada Rao Hari

Among all functional groups, alkynes occupy a privileged position in synthetic and medicinal chemistry, chemical biology, and materials science. Thioalkynes, in particular, are highly useful, as they combine the enhanced reactivity of the triple bond with ...

2014