- Synthesis of α,β-unsaturated esters of perfluoropolyalkylethers (PFPAEs) based on hexafluoropropylene oxide units for photopolymerization
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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.
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p. 32664 - 32671
(2018/10/15)
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- Stereoselective Formation of Maleic Acid Diester from Two Diazo Acetic Acid Esters on a Raney Nickel Surface. Evidence for Dipod-chemisorbed Carbenes
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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.
- Bock, Hans,Wolf, Hans Peter
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p. 690 - 692
(2007/10/02)
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- Palladium(II) Chloride Catalyzed Carbonylation of Organic Tellurides with Carbon Monoxide
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Various organic tellurides react with carbon monoxide (1 atm) at room temperature in methanol in the presence of PdCl2 and Et3N to afford the corresponding methyl carboxylates in good to excellent yields.The reaction is catalytic in PdCl2 when a suitable reoxidant such as CuCl2, CuCl/O2, FeCl3 or Ce(NH4)2(NO3)6 is present.The combination of this carbonylation with phenyltellurenylation of arylacetylenes and propargylic alcohols makes it possible to prepare ring-substituted cis-methyl cinnamates and Δα,β-butenolides, respectively.Both monomeric and dimeric palladium complexes, (Ph2Te)2PdCl2 and 2, react readily with CO to give a high yield of methyl benzoate.The key step of the present carbonylation is proposed to be the migration of an organic moiety from Te to Pd (transmetalation) in organic telluride-PdCl2 complexes, presumably formed in situ, to afford organopalladium compounds.
- Ohe, Kouichi,Takahashi, Hidetaka,Uemura, Sakae,Sugita, Nobuyuki
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p. 4859 - 4863
(2007/10/02)
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