- 2,2,5,5-Tetramethyltetrahydrofuran (TMTHF): A non-polar, non-peroxide forming ether replacement for hazardous hydrocarbon solvents
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An inherently non-peroxide forming ether solvent, 2,2,5,5-tetramethyltetrahydrofuran (2,2,5,5-tetramethyloxolane), has been synthesized from readily available and potentially renewable feedstocks, and its solvation properties have been tested. Unlike traditional ethers, its absence of a proton at the alpha-position to the oxygen of the ether eliminates the potential to form hazardous peroxides. Additionally, this unusual structure leads to lower basicity compared with many traditional ethers, due to the concealment of the ethereal oxygen by four bulky methyl groups at the alpha-position. As such, this molecule exhibits similar solvent properties to common hydrocarbon solvents, particularly toluene. Its solvent properties have been proved by testing its performance in Fischer esterification, amidation and Grignard reactions. TMTHF's differences from traditional ethers is further demonstrated by its ability to produce high molecular weight radical-initiated polymers for use as pressure-sensitive adhesives.
- Byrne, Fergal,Forier, Bart,Bossaert, Greet,Hoebers, Charly,Farmer, Thomas J.,Clark, James H.,Hunt, Andrew J.
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supporting information
p. 3671 - 3678
(2017/08/15)
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- Controlled Rearrangement of 2,3-Dilithio-1,3-butadienes to 2,5-Dilithio-1,3-butadienes: Synthesis of 2-Isopropylidene-2,5-dihydrosilols
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3,4-Dilithio-2,5-dimethyl-2,4-hexadiene (4a) rearranges to the cross-conjugated 2,5-dimethylhexadienediyl dianion 11a. A mechanistic investigation proves the intermolecularity of this rearrangement, which is also observed when starting from 4b. The 3-lithio-2,5-dimethylhexadienyl anion 10a with one vinyllithium and one allyllithium group, is a true intermediate in this rearrangement, its synthetic potential is employed in the reaction with dichlorosilanes to form 2-isopropylidene-2,5-dihydrosilols 8.
- Maercker, Adalbert,Wunderlich,Girreser, Ulrich
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p. 793 - 798
(2007/10/03)
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- Photochemical nucleophile-olefin combination, aromatic substitution (photo-NOCAS) reaction. Part 7: methanol, conjugated dienes, and 1,4-dicyanobenzene
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The scope of the photochemical nucleophile-olefin combination, aromatic substitution (photo-NOCAS) reaction has been extended to include conjugated dienes: 1,3-butadiene (9), 2-methyl-1,3-butadiene (10), 2,3-dimethyl-1,3-butadiene (11), and 2,5-dimethyl-2
- McManus, Kimberly A.,Arnold, Donald R.
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p. 2291 - 2304
(2007/10/02)
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- A Study of the Nature of the Allene-ene Intramolecular Cycloaddition Reaction. A Novel Allene-ene Reaction
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The thermally induced gas phase reactions of the ene-allene ketones 2,5,5-trimethylocta-1,6,7-trien-4-one (1a), 2,5,5-trimethylnona-1,6,7-trien-4-one (1b) and 2,5,5,8-tetramethyl-1,6,7-trien-4-one (1c) gave products from intramolecular cycloaddition
- Skattebol, Lars,Stenstrom, Yngve,Uggerud, Einar
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p. 363 - 369
(2007/10/02)
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- Titanium Catalyzed Cyclization of 1,5-Hexadienes
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Cp2TiCl (1) and Cp2TiCl2 (2) combined with isopropylmagnesium bromide (molar ratio 1:1 and 1:2, resp.) catalyze the conversion of 1,5-hexadiene into a mixture of the five-membered ring compounds 3 and 4 as well as the linear isomeric hexadienes 5, 6, and 7.THF is most effective in both promoting cyclization as well as suppressing isomerization (3 -> 4 and 5 -> 6 or 7).The ratio of cyclic to linear products in reactions involving substituted 1,5-hexadienes is found to be dependent upon the position of the substituents.Substitution in the 2- or 2- and 5-position leads to the formation of the open-chain isomers 11 and 12 or 13 and 14, while 3,4-substituted 1,5-hexadienes react to give > 99percent of the five-membered ring systems 15 and 16 or 17 and 18.A reaction mechanism is discussed which involves Cp2TiH and Cp2(alkenyl)Ti intermediates.
- Lehmkuhl, Herbert,Tsien, Yen-Lung
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p. 2437 - 2446
(2007/10/02)
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- Studies on the Conversions of Diols and Cyclic Ethers. Dehydration of Alcohols and Diols on the Action of Dimethylsulfoxide
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The transformations of 13 alcohols and 13 diols in the presence of a small amount dimethylsulfoxide (1/16 mol) were studied.Relationships were found between the type of the hydroxy compound and the selectivity of the transformation, and conclusions were drawn regarding the transformation mechanism.The ether formation observed with certain alcohols proceeds via a carbenium cation.The reaction conditions applied were found suitable for including water elimination from the ditertiary 1,2- and 1,3-diols (pinacol rearrangement, 1,2-elimination).From the 1,4- and 1,5-diols the corresponding oxacycloalkanes can be obtained in good yield.Cyclodehydration occurs by intramolecular nucleophilic substitution, via a concerted mechanism.The effect of DMSO is excerted directly, and proton-catalysis occurs simultaneously.
- Molnar, Arpad,Bartok, Mihaly
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p. 389 - 398
(2007/10/02)
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