Skip to Main content Skip to Navigation
Journal articles

Reactivity of benzylidene and alkylidenemalonates in radical addition mediated with dialkylzincs - An intriguing story

Abstract : Benzylidene- and alkylidenemalonates are extremely reactive radical acceptors in dialkylzinc-mediated radical additions. Theoretical investigations showed that the multi-step radical-polar crossover process should be highly exothermic. Not only the addition of the alkyl radical to the complexed substrate is enthalpically favored but what is more, the homolytic substitution at the metal leading to a zinc enolate should also be exothermic, even though it necessitates the cleavage of the C-Zn bond from the complexed alpha-alkoxycarbonyl radical intermediate. This work was undertaken to highlight the power of chelation in controlling the fate of this type of reaction. Much to our surprise, no unambiguous experimental evidence could be put forward to prove the formation of the expected zinc enolate intermediate. Additionally, benzylidenemalonates and their alkylidene analogues (although to a lesser extent) exhibit an intriguing behavior. The backward reaction (retr o-addition) can be triggered at work-up depending upon experimental conditions. (C) 2018 Elsevier Ltd. All rights reserved.
Document type :
Journal articles
Complete list of metadatas

https://hal-amu.archives-ouvertes.fr/hal-02091868
Contributor : Didier Gigmes <>
Submitted on : Saturday, April 6, 2019 - 5:16:21 PM
Last modification on : Friday, February 14, 2020 - 6:02:05 PM

Identifiers

Collections

Citation

Hugo Lingua, Nejib Dwadnia, Didier Siri, Michèle P. Bertrand, Laurence Feray. Reactivity of benzylidene and alkylidenemalonates in radical addition mediated with dialkylzincs - An intriguing story. Tetrahedron, Elsevier, 2018, 74 (52), pp.7507--7515. ⟨10.1016/j.tet.2018.11.029⟩. ⟨hal-02091868⟩

Share

Metrics

Record views

87