Publications by Julien Aymeric Borrel

Novel Alkynylation Methods through the Combination of Hypervalent Iodine Reagents and Alkynyl-trifluoroborate Salts

The alkyne motif is a versatile functional group often encountered in organic chemistry. It can be involved in various transformations such as the alkyne-azide cycloaddition and has found widespread application in medicinal chemistry, chemical biology and ...

EPFL2024

SOMOphilic alkyne vs radical-polar crossover approaches: The full story of the azido-alkynylation of alkenes

Jérôme Waser, Julien Aymeric Borrel

We report the detailed background for the discovery and development of the synthesis of homopropargylic azides by the azidoalkynylation of alkenes. Initially, a strategy involving SOMOphilic alkynes was adopted, but only resulted in a 29% yield of the desi ...

Beilstein-Institut2024

Acyl-Ethynylbenziodoxolone (acyl-EBX): Access to Ketene Dithioarylacetals

Jérôme Waser, Maël Djaïd, Julien Aymeric Borrel, Pierre Gérard Joseph Palamini, Morgane Elodie Marie Delattre

We report the synthesis of ketene dithioarylacetals in 40–97% yield using thiophenols and acyl-EBXs (ethynylbenziodoxolones) generated in situ from a common hypervalent iodine precursor and alkynyl trifluoroborate salts. The products could be further modif ...

2023

Azido-alkynylation of alkenes through radical-polar crossover

Jérôme Waser, Julien Aymeric Borrel

We report an azido-alkynylation of alkenes allowing a straightforward access to homopropargylic azides by combining hypervalent iodine reagents and alkynyl-trifluoroborate salts. The design of a photocatalytic redox-neutral radical polar crossover process ...

2023

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

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

Copper-Catalyzed Oxyalkynylation of C-S Bonds in Thiiranes and Thiethanes with Hypervalent Iodine Reagents

Jérôme Waser, Guillaume Dominique Pisella, Julien Aymeric Borrel

We report the oxyalkynylation of thiiranes and thietanes using ethynylbenziodoxolone reagents (EBXs) to readily access functionalized building blocks bearing an alkynyl, a benzoate, and an iodide group. The reaction proceeds with high atom efficiency most ...

2019