Stereoselective Formation of Maleic Acid Diester from Two Diazo Acetic Acid Esters on a Raney Nickel Surface. Evidence for Dipod-chemisorbed Carbenes
The N2 elimination from diazo acetic acid esters, heterogeneously catalysed by Raney Nickel, yields as chemidesorbed main product up to 93percent maleic acid diester, cis-stereoselectivity is observed and additional methyl/ethyl ester crossing experiments provide evidence for dipod-chemisorbed surface carbene intermediates.
Synthesis of α,β-unsaturated esters of perfluoropolyalkylethers (PFPAEs) based on hexafluoropropylene oxide units for photopolymerization
α,β-unsaturated esters are usually synthesized for polymer applications. However, the addition of maleate (cis-configuration) to a fluorinated moiety is challenging due to its potential isomerization during esterification. Various synthetic routes were attempted and led to very low conversion or side-products. The immiscibility of both reagents combined with an easy isomerization or attack on the double bond were potential explanations. In this paper, the synthesis of maleates oligo(hexafluoropropylene oxide) is reported by Steglich esterification and the reaction conditions are discussed depending on the molecular weight of the fluorinated moieties. After UV-curing, hydrophobic polymers were obtained by copolymerization with vinyl ethers by electron acceptor-donor systems.
Bonneaud, Céline,Decostanzi, Mélanie,Burgess, Julia,Trusiano, Giuseppe,Burgess, Trevor,Bongiovanni, Roberta,Joly-Duhamel, Christine,Friesen, Chadron M.
p. 32664 - 32671
(2018/10/15)
Cyclopropanation Catalysed by RuCl2(PPh3)3 and OsCl2(PPh3)3
OsCl2(PPh3)3 is a cyclopropanation catalyst using ethyl diazoacetate with a variety of activated alkenes; OsCl2(PPh3)3 is however less active than RuCl2(PPh3)3 for the decomposition of the diazo reagent and the subsequent cyclopropanation.
Demonceau, A.,Lemoine, C. A.,Noels, A. F.,Chizhevsky, I. T.,Sorokin, P.V.
p. 8419 - 8422
(2007/10/02)
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