Isomerisation of (E)-2-Tetrahydrofurylidenealkanecarboxylic Esters and Amides into Their (Z) Isomers by Chelation Control with Metallated Bases or Lewis Acids - Université de Montpellier Accéder directement au contenu
Article Dans Une Revue European Journal of Organic Chemistry Année : 2002

Isomerisation of (E)-2-Tetrahydrofurylidenealkanecarboxylic Esters and Amides into Their (Z) Isomers by Chelation Control with Metallated Bases or Lewis Acids

Résumé

2-(2-Tetrahydrofurylidene)propionates, usually obtained only in the more stable (E) configuration 1, were efficiently isomerised into their (Z) isomers 2 by use of Lewis acids or metallated bases. The (E)/(Z) isomerisation was governed by different factors (type of chelating agent, nature and steric demand of the α,β-unsaturated group). We demonstrated that judicious selection of the α,β-unsaturated group, in combination with the chelating agent, afforded yields of up to 95% with either LDA [R = N(Me)2, tBu] or MgBr2 and ZnI2 (R = OBn), and that the reaction was also influenced by 1,3-allylic strains.

Domaines

Chimie organique

Dates et versions

hal-03468864 , version 1 (08-12-2021)

Identifiants

Citer

Gilles Hanquet, Xavier J Salom-Roig, Sonia Lemeitour, Guy Solladié. Isomerisation of (E)-2-Tetrahydrofurylidenealkanecarboxylic Esters and Amides into Their (Z) Isomers by Chelation Control with Metallated Bases or Lewis Acids. European Journal of Organic Chemistry, 2002, 2002 (13), pp.2112-2119. ⟨10.1002/1099-0690(200207)2002:13<2112::AID-EJOC2112>3.0.CO;2-%23⟩. ⟨hal-03468864⟩
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