Thermally catalyzed and noncatalyzed [2 + 2] cycloadditions between ketene acetals and carbonyl compounds. A simple route to 2,2-dialkoxyoxetanes

Scheeren, Hans W.; Aben, R. W. M.; Ooms, Pieter H. J.; Nivard, R. J. F.

doi:10.1021/jo00439a005

Cited by 48 publications

(4 citation statements)

References 6 publications

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“…Hydrocarbon oxetanes were reported to react with alcohols under relatively mild conditions [13]. It is interesting, that electron deficient oxetanes 1 also have similar reactivity and rapidly react with alcohols in the absence of the catalyst.…”

Section: Resultsmentioning

confidence: 99%

Acid catalyzed cyclodimerization of 2,2-bis(trifluoromethyl)-4-alkoxy-oxetanes and -thietanes. Synthesis of 2,2,6,6-tetrakis(trifluoromethyl)-4,8-dialkoxy-1,5-dioxocanes and 3,3,7,7-tetrakis(trifluoromethyl)-9-oxa-2,6-dithia-bicyclo[3.3.1]nonane

Петров¹,

Marshall²

2010

Beilstein J. Org. Chem.

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SummaryTreatment of 2,2-bis(trifluoromethyl)-4-R-oxetanes (R = C2H5O, n-C3H7O, n-C4H9O) with BF3·OEt2 in CH2Cl2 solvent results in spontaneous electrophilic [4 + 4] cyclodimerization with the formation of the corresponding 2,2,6,6-tetrakis(trifluoromethyl)-4,8-dialkoxy-1,5-dioxocanes, isolated in 31–42% yield. The structures of two products (R = C2H5O and n-C3H7O) were established by single crystal X-ray diffraction. The corresponding oxetane carrying the bulky t-C4H9O group has different reactivity towards BF3·OEt2, slowly producing a mixture of two acyclic, unsaturated products.Clean and spontaneous reaction with alcohols is another interesting transformation of oxetanes described in this paper. The reaction leads to high yield formation of the corresponding acetals (CF3)2C(OH)CH2CH(OR)OR′.Structurally related 2,2-bis(trifluoromethyl)-4-R-thietanes (R = i-C3H7O, t-C4H9O and C2H5O) have different reactivity towards electrophiles. They are totally inert to the action of BF3·OEt2 and rapidly react with a protic acid (H2SO4) forming the same product, 3,3,7,7-tetrakis(trifluoromethyl)-9-oxa-2,6-dithia-bicyclo[3.3.1]nonane in 35–50% yield. The structure of this product was established by single crystal X-ray diffraction.

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Section: Resultsmentioning

confidence: 99%

Acid catalyzed cyclodimerization of 2,2-bis(trifluoromethyl)-4-alkoxy-oxetanes and -thietanes. Synthesis of 2,2,6,6-tetrakis(trifluoromethyl)-4,8-dialkoxy-1,5-dioxocanes and 3,3,7,7-tetrakis(trifluoromethyl)-9-oxa-2,6-dithia-bicyclo[3.3.1]nonane

Петров¹,

Marshall²

2010

Beilstein J. Org. Chem.

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“…The enol ethers (Aldrich) were distilled from CaH 2 before use. The ketene acetals were prepared according to the literature procedures and were distilled from CaH 2 and stored in resealable ampules at −25 °C in a desiccator. , Nitrone 1 and C -phenyl- N -benzyl nitrone were prepared according to the literature methods . All of the nitrones were sublimed prior to use and stored in an argon-filled glovebox.…”

Section: Methodsmentioning

confidence: 99%

Homogeneous Catalysis. Metallocene Catalysts for [3+2] Nitrone−Olefin Cycloaddition Reactions

et al. 1999

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The complex [Cp2Ti(OTf)2] is a catalyst for the [3+2] cycloaddition of nitrones with electron-rich olefins. In the presence of small amounts of water, catalyst hydrolysis leads to the production of triflic acid, which is a powerful catalyst for these cycloaddition reactions. Acid catalysis can be suppressed by the use of Proton-Sponge. Metal catalysis appears to proceed via the bis(nitrone) adduct [Cp2Ti(nitrone)2]2+. A crystal structure of one of these adducts is reported.

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“…Indeed, some reactions of HFTA with ''soft'' nucleophiles have been reported to occur through the attack on sulfur [9]. The ethylene 2 is known to be highly nucleophilic and it was reported to react with electron-deficient materials such as carbonyl compounds [10], diazopyrazoles [11] and acetylenic esters [12]. These reactions rapidly proceed at ambient temperature and in the absence of a catalyst.…”

Section: (8)mentioning

confidence: 99%

“…These reactions rapidly proceed at ambient temperature and in the absence of a catalyst. For example, for the [2 + 2] cycloaddition reaction between chloral and 2 in CDCl 3 the t 1/2 was reported to be less than 1 min at 25 8C [10].…”

Section: (8)mentioning

confidence: 99%

Reaction of hexafluorothioacetone dimer with ketene dimethylacetal and dimethyl thioacetal

Петров

Marshall

2012

Journal of Fluorine Chemistry

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Thermally catalyzed and noncatalyzed [2 + 2] cycloadditions between ketene acetals and carbonyl compounds. A simple route to 2,2-dialkoxyoxetanes

Cited by 48 publications

References 6 publications

Acid catalyzed cyclodimerization of 2,2-bis(trifluoromethyl)-4-alkoxy-oxetanes and -thietanes. Synthesis of 2,2,6,6-tetrakis(trifluoromethyl)-4,8-dialkoxy-1,5-dioxocanes and 3,3,7,7-tetrakis(trifluoromethyl)-9-oxa-2,6-dithia-bicyclo[3.3.1]nonane

Acid catalyzed cyclodimerization of 2,2-bis(trifluoromethyl)-4-alkoxy-oxetanes and -thietanes. Synthesis of 2,2,6,6-tetrakis(trifluoromethyl)-4,8-dialkoxy-1,5-dioxocanes and 3,3,7,7-tetrakis(trifluoromethyl)-9-oxa-2,6-dithia-bicyclo[3.3.1]nonane

Homogeneous Catalysis. Metallocene Catalysts for [3+2] Nitrone−Olefin Cycloaddition Reactions

Reaction of hexafluorothioacetone dimer with ketene dimethylacetal and dimethyl thioacetal

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