Séminaire de Christophe Bour

Le 16 Février 2024, Salle Jean Barriol,

Dr Christophe Bour, MCF à l’Université Paris-Saclay, ICMMO (UMR 8182), donnera une conférence intitulée « The renewed interest in vinyl cations as reactive intermediates ».

Vinyl cations, long overlooked due to their supposed uncontrollable nature, have recently
become the focus of renewed research into their physical and chemical properties.1 This has led
to exciting new applications in homogeneous catalysis. The Mayr group has played a pivotal role
in dispelling the myths surrounding these intermediates, revealing that their stability is
comparable to that of tertiary carbocations.2 Nevertheless, due to the substantial energy barrier
associated with sp«sp2 rehybridization, vinyl cations tend to be sluggish electrophiles.
Building on this breakthrough, several research groups have addressed this electrophilicity
issue and have successfully harnessed vinyl cations to develop novel reactions. Our group, in
particular, has devised a gentle and effective method for the bimolecular vinylation of arenes.3 This
involves employing a lithium salt as a catalyst to activate vinyl triflates and facilitate the formation
of a vinyl carbocation. Furthermore, we have extended this strategy to conduct substitution
reactions between vinyl cations and various nucleophiles, both in inter- and intramolecular
settings.4
References:
1. Squaramide/Li+
-Catalyzed Direct SN1-Type Reaction of Vinyl Triflates with Difluoroenoxysilanes through Vinyl Cations
Chen. Y.; Gandon, V.* Bour, C.*; Org. Lett., 2022, 24, 6978.
2. Potassium Carbonate to Unlock a GaCl3-Catalyzed C–H Propargylation of Arenes. Vayer, M.; Rodrigues, S.;
Miaskiewicz, S.; Gatineau, D.; Gimbert, Y.; Gandon, V.*; Bour, C. *ACS Catal., 2022, 12, 305.
3. Bimolecular vinylation of arenes by vinyl cations. Li, Z.; Gandon, V.; Bour, C. Chem. Commun. 2020, 56, 6507.
4. Synthesis of Medium-Sized Carbocycles by Gallium-Catalyzed Tandem Carbonyl–Olefin Metathesis/Transfer
Hydrogenation. Djurovic, A.; Vayer, M.; Li, Z.; Guillot, R.; Baltaze, J.-P.; Gandon, V.; Bour, C.* Org. Lett. 2019, 21, 8132.
5. Iron-Catalyzed Reductive Ethylation of Imines Using Ethanol. Vayer, M.; Morcillo, S.; Dupont, J.;
Gandon, V.; Bour, C.* Angew. Chem. Int. Ed. 2018, 57, 3228.