Publications associées à Wittig rearrangement of lithiated allyl aryl ethers: a mechanistic study

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

How much metal did the first stars provide to the ultra-faint dwarfs?

Yves Revaz, Pascale Jablonka, Mahsa Sanati

Numerical simulations of dwarf galaxies have so far failed to reproduce the observed metallicity-luminosity relation, down to the regime of ultra-faint dwarfs (UFDs). We address this issue by exploring how the first generations of metal-free stars (Pop III ...

EDP SCIENCES S A2023

COSMOS-Web: An Overview of the JWST Cosmic Origins Survey

Richard Massey, Michaela Hirschmann

We present the survey design, implementation, and outlook for COSMOS-Web, a 255 hr treasury program conducted by the James Webb Space Telescope in its first cycle of observations. COSMOS-Web is a contiguous 0.54 deg² NIRCam imaging survey in four filters ( ...

IOP Publishing Ltd2023

Ring-Opening Reactions of Aminocyclopropanes and Aminocyclobutanes

Mingming Wang

Nitrogen-containing compounds are an important class of molecules in medicinal chemistry, chemical biology, biochemistry, material sciences or environmental sciences. Organic nitrogen occurs in many forms, ranging from small building blocks such as urea, a ...

EPFL2022

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

Rh-catalyzed C-H Bond Heteroarylation with Hypervalent Iodine Reagents and Pd-Catalyzed Tethered Functionalizations of Carbon-Carbon Multiple Bonds

Ashis Kumar Das

Transition metal-catalyzed C-H activation is a powerful tool for the synthesis of organic building blocks, materials, and natural products. Over the last decade, directing-group-assisted metal-catalyzed C-H functionalization has attracted increasing intere ...

EPFL2022

Chiral Cyclic Alkyl Amino Carbene (CAAC) Transition-Metal Complexes: Synthesis, Structural Analysis, and Evaluation in Asymmetric Catalysis

Adrien Jules Louis Madron Du Vigné

Despite recent advances in the field of cyclic alkyl amino carbenes (CAACs) including a few complementary synthetic strategies affording CAACs with various substitution patterns, the application potential of chiral CAACs to efficiently catalyze asymmetric ...

2022

Umpolung Of Electron-Rich Heteroarenes With Hypervalent Iodine Reagents

Jérôme Waser, Raj Kumar Nandi

Five-membered heterocycles are well known for their innate nucleophilicity. In contrast, reaction of these heterocycles as electrophiles is less established and has become only recently an intensively investigated research area in synthetic chemistry. The ...

PERGAMON-ELSEVIER SCIENCE LTD2021

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

New Vinylation and Alkynylation Strategies with Hypervalent Iodine Reagents and Diazo Compounds

Guillaume Dominique Pisella

The development of a sequential copper-catalyzed oxy-alkynylation/intramolecular [4+2] cycloaddition of allenes and arenes was investigated at first. This one-pot protocol allowed the construction of complex polycylic architectures with high efficiency fro ...

EPFL2021

Diamine Synthesis via the Nitrogen-Directed Azidation of sigma- and pi-C-C Bonds

Jérôme Waser, Mingming Wang

Diamines are essential building blocks for the synthesis of agrochemicals, drugs, and organic materials, yet their synthesis remains challenging, as both nitrogens need to be differentiated and diverse substitution patterns (1,2, 1,3, or 1,4) are required. ...

2021

The Pristine Inner Galaxy Survey (PIGS) III: carbon-enhanced metal-poor stars in the bulge

Pascale Jablonka, Carmela Lardo

The most metal-deficient stars hold important clues about the early buildup and chemical evolution of the Milky Way, and carbon-enhanced metal-poor (CEMP) stars are of special interest. However, little is known about CEMP stars in the Galactic bulge. In th ...

OXFORD UNIV PRESS2021

Oxidative Fluorination of Cyclopropylamides through Organic Photoredox Catalysis

Jérôme Waser, Mingming Wang

We report an oxidative ring-opening strategy to transform cyclopropylamides and cyclobutylamides into fluorinated imines. The imines can be isolated in their more stable hemiaminal form, with the fluorine atom installed selectively at the gamma or delta po ...

Wiley-VCH Verlag GmbH2020

Oxygen evolution reaction catalyzed by first-row transition metal oxides: stability and mechanism

Aliki Moysiadou

Water splitting offers the opportunity for storing solar energy and, thus, producing carbon-neutral and renewable solar fuels. The process, known as artificial photosynthesis, is limited by the electrocatalytic conversion of water into molecular oxygen. El ...

EPFL2020

Molecular-Level Transformation of Dissolved Organic Matter during Oxidation by Ozone and Hydroxyl Radical

Urs von Gunten

Ozonation of drinking and wastewater relies on ozone (O-3) and hydroxyl radical ((OH)-O-center dot) as oxidants. Both oxidants react with dissolved organic matter (DOM) and alter its composition, but the selectivity of the two oxidants and mechanisms of re ...

AMER CHEMICAL SOC2020

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

Reactions of nitrogen-containing compounds with ozone: kinetics and mechanisms

Sung Eun Lim

Nitrogen-containing moieties are widespread in natural waters in dissolved organic nitrogen and micropollu-tants. They are often susceptible to an electrophilic attack of ozone because of the electron-rich nature of the neutral form of nitrogen in organic ...

EPFL2020

The chemical evolution of the dwarf spheroidal galaxy Sextans

Pierre North, Romaine Theler, Pascale Jablonka, Carmela Lardo, Romain Ely Roland Lucchesi

We present our analysis of the FLAMES dataset targeting the central 25 ' region of the Sextans dwarf spheroidal galaxy (dSph). This dataset is the third major part of the high-resolution spectroscopic section of the ESO large program 171.B-0588(A) obtained ...

EDP SCIENCES S A2020

Mechanism of Oxygen Evolution Catalyzed by Cobalt Oxyhydroxide: Cobalt Superoxide Species as a Key Intermediate and Dioxygen Release as a Rate-Determining Step

Xile Hu, Aliki Moysiadou, Seunghwa Lee

The oxygen evolution reaction (OER) is the performance-limiting half reaction of water splitting, which can be used to produce hydrogen fuel using renewable energies. Whereas a number of transition metal oxides and oxyhydroxides have been developed as prom ...

2020

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