Publications de Franck Le Vaillant

Exploring Photoredox-Catalyzed (Re)functionalizations with Core-Modified Benziodoxolones

Jérôme Waser, Franck Le Vaillant, Stephanie Grace Elizabeth Amos

Alkynes and nitriles are valuable building blocks in organic synthesis and also have multiple applications in chemical biology and materials science. Due to the high availability of tertiary alcohols, developing methods for their conversion into alkynes an ...

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

C-Terminal Bioconjugation of Peptides through Photoredox Catalyzed Decarboxylative Alkynylation

Jérôme Waser, Franck Le Vaillant, Marion Marie-Agnès Garreau

We report the first decarboxylative alkynylation of the C-terminus of peptides starting from free carboxylic acids. The reaction is fast, metal-free, and proceeds cleanly to afford alkynylated peptides with a broad tolerance for the C-terminal amino acid. ...

Wiley-VCH Verlag GmbH2019

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

Metal-Free Electrophilic Alkynylation of Sulfenate Anions with Ethynylbenziodoxolone Reagents

Jérôme Waser, Stefano Nicolai, Franck Le Vaillant, Alec Gagnebin, Stephanie Grace Elizabeth Amos

Alkynyl sulfoxides are important building blocks with a unique reactivity in organic chemistry, but only a few reliable methods have been reported to synthesize them. A novel route to access alkynyl sulfoxides is reported herein by using ethynyl benziodoxo ...

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

Revisiting the Urech Synthesis of Hydantoins: Direct Access to Enantiopure 1,5-Substituted Hydantoins Using Cyanobenziodoxolone

Jérôme Waser, Franck Le Vaillant, Nina Declas

A method for the synthesis of enantiopure 1,5-substituted hydantoins was developed using a hypervalent iodine cyanation reagent (cyanobenziodoxolone, CBX) as a source of electrophilic carbon. Starting from inexpensive commercially available enantiopure pro ...

2019

Fine-Tuned Organic Photoredox Catalysts for Fragmentation-Alkynylation Cascades of Cyclic Oxime Ethers

Jérôme Waser, Franck Le Vaillant, Stefano Nicolai, Ganna Gryn'ova, Marion Marie-Agnès Garreau

2018

Decarboxylative Alkynylation and Cyanation of Carboxylic Acids using Photoredox Catalysis and Hypervalent Iodine Reagents

Jérôme Waser, Franck Le Vaillant

Alkynes and nitriles are important functional groups that serve as versatile building blocks in organic synthesis and find applications in material and medicinal sciences. A convenient and straightforward access to both classes of compounds under mild cond ...

2017

Room temperature decarboxylative cyanation of carboxylic acids using photoredox catalysis and cyanobenziodoxolones: a divergent mechanism compared to alkynylation

Jérôme Waser, Matthew Wodrich, Franck Le Vaillant

The one-step conversion of aliphatic carboxylic acids to the corresponding nitriles has been accomplished via the merger of visible light mediated photoredox and cyanobenziodoxolones (CBX) reagents. The reaction proceeded in high yields with natural and no ...

2017