Nouvelle méthode de préparation d'éthers vinyliques à partir d'acétals

Abstract

A new way to vinylic ethers from acetalsSummary Acetals react at low temperatures in presence of a Lewis acid (aluminium chloride or magnesium bromide) with tertiary amine to give in good yields the vinylic ethers corresponding to the elimination of one molecule of alcohol. ether (CH2= CH-CH,),Al,Br,

Novel Partially Fluorinated Copolymers: Evidence of the Effect of Fluorine on the Reactivity of the Unfluorinated Comonomer Units

“…Butyl isopropenyl ether (BPE) was synthesized following the method reported by Barbot and Miginiac. [5] Azobis-1,1-dimethyl-2-propionitrile (2,2-azoisobutyronitrile, AIBN, purified by recrystallization from ethanol) and Perkadox TM 16 (4,4 0 -tert-butylcyclohexylperoxydicarbonate) were kind gifts from Akzo-Nobel, Italy.…”

Eco‐Mn Ecocatalysts: Toolbox for Sustainable and Green Lewis Acid Catalysis and Oxidation Reactions

“…However, it is also possible to synthesize alkyl enol ethers from aldehydes, by acetalization with an alcohol under acid catalysis, then removal of the alcohol, under acid or base catalysis . The elimination step is generally carried out with the use of aggressive Brønsted acids, such as sulfuric acid or p ‐toluenesulfonic acid or readily hydrolysable Lewis acids, such as aluminum . This step can also be accomplished by co‐catalysis with aluminum chloride and a non‐nucleophilic base, such as triethylamine .…”

“…[59] This step can also be accomplished by co-catalysis with aluminum chloride and a non-nucleophilic base, such as triethylamine. [59] Noticeably, none of these conditions are in accordance with the principles of green chemistry. Given the double acid nature of Eco-Mn LA1 as hard Lewis and Brønsted acids, the formation of ethyl enol ether from carbonyl derivatives is possible (Scheme 9).…”

“…The elimination step is generally carried out with the use of aggressive Brønsted acids, such as sulfuric acid or p ‐toluenesulfonic acid or readily hydrolysable Lewis acids, such as aluminum . This step can also be accomplished by co‐catalysis with aluminum chloride and a non‐nucleophilic base, such as triethylamine . Noticeably, none of these conditions are in accordance with the principles of green chemistry.…”

γ-Carbolines and their hydrogenated derivatives. 2.* Hydrogenated derivatives of γ-carbolines: methods of synthesis (review)

“…The initial enolic ethers of N-phenylsulfonylpiperid-4-one are obtained from its dimethyl acetal by the action of aluminum chloride and triethylamine [81]. It is seen from the presented data that only the tetrahydro-γ-carboline derivative 28 is formed in the presence of an excess of the complex catalyst TiCl 4 -Ti(OPr-i) 4 (1:1), whereas the reaction with the addition of boron trifluoride etherate leads to the formation of only the benzofuran adduct 29.…”