Bromine-lithium exchange on gem-dibromoalkenes part 1: batch vs microflow conditions

Baptiste Picard (1) , Katia Pérez (1, 2) , Thomas Lebleu (1) , Daniela Vuluga (2) , Fabrice Burel (2) , David Harrowven (3) , Isabelle Chataigner (1, 4) , Jacques Maddaluno (1) , Julien Legros (1)

1 COBRA - Chimie Organique et Bioorganique : Réactivité et Analyse
2 PBS - Polymères Biopolymères Surfaces
3 University of Southampton
4 LCT - Laboratoire de chimie théorique

The generation and reactivity of two model vinyl carbenoids from gem-dibromoalkenes 1 CRlRs=CBr2 were studied in microflow systems. From substrate 1a (R = Ph, CF3), the lithium-bromine exchange could be simply performed within 30 ms at 20 °C with very good E-selectivity whereas the reaction was unselective under batch conditions, even at −78 °C. Moreover, the unstable carbenoid generated from 1b (R = Ph, H) could be trapped as the major product while only the Fritsch-Buttemberg-Wiechell rearrangement product was obtained in a flask under cryogenic conditions.

Mots clés: Fritsch-Buttemberg-Wiechell rearrangement; carbenoid; organolithium compounds; selectivity; microfluidics

Domaines: Chimie organique; Génie chimique

Baptiste Picard, Katia Pérez, Thomas Lebleu, Daniela Vuluga, Fabrice Burel, et al.. Bromine-lithium exchange on gem-dibromoalkenes part 1: batch vs microflow conditions. Journal of flow chemistry, 2020, 10 (1), pp.139-143. ⟨10.1007/s41981-019-00057-6⟩. ⟨hal-02996922⟩