Nucleophilic Addition to Acetylenes in Superbasic Catalytic Systems: XIII. Fluoride Cesium Containing Systems, Efficient Catalysts for Alkanols Vinylation

Abstract

New catalytic systems CsFMOH (M = Li, Na) were developed for the synthesis of alkyl vinyl ethers comparable in efficiency to cesium alcoholates. The addition of primary and secondary alcohols to acetylene occurs in the presence of these systems at the atmospheric (DMSO, 100°C) or at enhanced (without solvent, 135 140°C) acetylene pressure and affords alkyl vinyl ethers in up to 93% yield. * For communication XII see [1]. The systematic investigation of alcohols vinylation with acetylenes discovered by A.E. Faworsky [2] and further developed by W. Reppe [3] and M.F.Shostakovskii [4] provide deeper theoretical insight into the nucleophilic additions to the triple bond [5] and constant refining of the synthesis of vinyl ethers of versatile structures [3 12].Here the main trend in stimulating vinilation reaction is the application of superbasic systems, like alkali metal hydroxidepolar solvent lacking hydroxy groups (DMSO, N-methylpyrrolidone, HMPA) [5, 712], or alkali metal alcoholateLewis base (Crown ether)solvent lacking hydroxy groups (hydrocarbon) [13,14].We report here on the application of highly basic systems CsFMOH and CsFMOHDMS (M = Li, Na) as efficient catalysts to alcohols vinylation.In [15,16] it was shown by an example of 1-heptanol vinylation under enhanced and atmospheric acetylene pressure in the presence of alkali metal hydroxides that the catalysts under investigation fit to the following series according to the decreasing efficiency:The comparison of the catalytic activity of KOH hydrates (2KOH·H 2 O and KOH·H 2 O) confirmed the known [4,7] negative effect of water on the vinylation process. Consequently, the use of anhydrous alkali metal hydroxides, first of all of CsOH would considerably accelerate the vinylation of the hydroxy compounds. However the preparation of anhydrous cesium and rubidium is a laborious process. Usually azeotropic removal of water is used with an appropriate high-boiling solvent (octane, toluene). The present article contains findings evidencing the possibility of a successful application to the vinyl ethers synthesis of a catalytic system CsFMOH (M = Li, Na) where the anhydrous CsOH is formed directly in the course of vinylation. This system possesses significant advantages compared to traditional vinylation catalysts like sodium and potassium hydroxides.The high catalytic efficiency of the system developed is apparently due predominantly to the exchange between the lithium or sodium hydroxides and cesium fluoride resulting in cesium hydroxide and sparingly soluble lithium or sodium fluorides.The nature of the alkali metal cation in the MOH (where M = Li, Na) used in the catalytic couple CsF MOH did not virtually affect the rate of vinylation in keeping with the preliminary occurrence of the exchange reaction and with the actual catalysis of alcohol vinylation by the arising cesium hydroxide. The formation of sparingly soluble lithium and sodium fluorides shifts the exchange equilibrium to the right. Therewith the better solubility in alcohols of NaOH compared to...

Towards C1 chemistry: methanol vinylation by CaC2 in water in the presence of potassium or sodium carbonates

“…A series of experiments was conducted with water/DMSO mixture as a solvent ( Table 1, entries 4-6). This option was stimulated by previous investigations both experimental 5,8,[38][39][40] and theoretical [40][41][42][43] proving that the superbasic media like KOH/DMSO(water) actively catalyse the nucleophilic additions to acetylenes. In particular, it was shown that in the KOH/DMSO catalytic media, methanol was smoothly vinylated with acetylene gas at 80-120 ∘ C and atmospheric pressure.…”

Three-Component Reaction between Vinyl Ethers, Secondary Phosphines, and Elemental Selenium: One-Pot Synthesis of 1-(Alkoxy)ethyl and 1-(Aryloxy)ethyl Phosphinodiselenoates

“…1,4-Dioxane and Et 2 O were dried and freshly distilled from metallic Na before use. Vinyl ethers 1a-c, 15 1d,e, 16 1f, 17 and 1k 18 were prepared according to the published methods. Vinyl ethers 1g-i and the 1,4-bis(vinyloxy)benzene were synthesized by direct vinylation of the corresponding phenol or hydroquinone with acetylene in KOH-DMSO suspension (unpublished data).…”

Nucleophilic Addition to Acetylenes in Superbasic Catalytic Systems: XIV. Vinilation of Diols in a System CsF-NaOH

“…2, curve 3). Under comparable conditions [1] the yield of vinyl heptyl ether obtained by vinylation of 1-heptanol was 87%.…”

“…Therefore the search for new catalysts for the efficient and selective synthesis of mono-and divinyl ethers from diols remains an urgent problem. With this goal we have for the first time studied a reaction of acetylene with diols in the presence of a new catalytic system CsFNaOH [1,14] whose efficiency is due apparently mainly to the formation in situ of anhydrous cesium hydroxide nanoparticles. The an-hydrous cesium hydroxide is known to be more active [15] but less available than KOH vinylation catalyst.…”

“…Table 3. Vinylation of diols Ia, IcIe, and Ig in the presence of CsFNaOHDMSO at atmospheric acetylene pressure a It turned out that the vinylation of diols in the superbasic system CsFNaOHDMSO occurred less efficiently than the vinylation of monohydric alcohols [1]. Thus, in the presence of catalyst CsFNaOH (10 mol% each, corresponding to the concentration of 5/5 mol% to every hydroxy group) in the reaction mixture after heating to 100°C for 56 h was identified alongside initial 1,4-butanediol (Ie) predominantly monovinyl ether (yield 30%), and the yield of divinyl ether IIIe was no more than 10% (Table 3, run no.…”