Steric driving forces in perester decomposition. tert-Butylperoxy di-tert-butylacetate

Abruscato, Gerald J.; Tidwell, Thomas T.

doi:10.1021/ja00757a080

Cited by 7 publications

(4 citation statements)

References 1 publication

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“…most favorable cases. [6][7][8][9][10][11][12][13][14][15] This, however, is consistent with the results of the pressure studies. Since "normal" values of AV* for homolytic bond scission are +4 to +5 ml/mol,lb the contributions from solvation are on the order of -2 to -3 ml/mol; in contrast, reactions leading to formation of ions (e.g., solvolysis) not atypically show values of AV* as "large" as -20 ml/mol.lb•20…”

Section: Resultssupporting

confidence: 82%

High pressure studies. XV. Effects in aliphatic perester decomposition

Neuman¹,

Pankratz²

1973

J. Am. Chem. Soc.

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The activation volume for thermal decomposition of tert-butyl perpivalate in cumene ranges from ca. $0.3 to + 1.9 ml/mol over a 5000 atm pressure range, while that for tert-butyl perisobutyrate in the same solvent changes from cu. +1.6 to +3.2 ml/mol over the same range. It is proposed that these results indicate that twobond aliphatic perester thermolyses are characterized by polar contributions in their decomposition transition states. olar effects in free-radical reactions are a subject of continuing interest and debate. They have been proposed to account for rate correlations with the Hammett equation, particular selectivity patterns in competitive hydrogen abstractions, and solvent effects, among others. Classic examples have included the effect of substituents on hydrogen abstraction from substituted toluenes3-j and on the decomposition rates of tert-butyl phenylperacetates.6-8

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Section: Resultssupporting

confidence: 82%

High pressure studies. XV. Effects in aliphatic perester decomposition

Neuman¹,

Pankratz²

1973

J. Am. Chem. Soc.

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“…The reaction mixture was heated at reflux for 3 h, then cooled and poured onto ice. Workup by careful acidification, ether extraction, evaporation of solvent, and recrystallization from ethyl acetate gave 17.3 g (88%) of 16: mp 146-148.5 °C; lH NMR (CDC13-D20) S 0.88 (s, 3 H, CHa), 1.75 (m, J = 9.3, 5, 2 Hz, 1 H, H-8), 3.05-3.72 (m, 5 ), 4.02 (d, J = 2 Hz, 1 , H-4), 7.16 (19). A saturated solution of 2 g (7.2 mmol) of 16 in anhydrous ether was prepared at 0 °C and 1.1 g (14 mmol) of pyridine was added.…”

Section: Discussionmentioning

confidence: 99%

“…Anhydrous hydrogen sulfide was bubbled through this medium until saturation. About 3.8 g (7.2 mmol) of 19 (which was dried by evaporating the benzene from its benzene solution) was then washed into this reaction medium using a minimum of anhydrous ethanol. The solution was refluxed for 3 days, using a condenser fitted with a CaSOi drying tube.…”

Section: Discussionmentioning

confidence: 99%

“…Although the reduction of the analogue of 19 without the methyl group (and with p-toluenesulfonoxy groups) proceeds to give 4 in fair yield when special conditions are used, that of 19 led rather to the tetrahydrofuran 18, presumably via attack at sulfur to give the monoester,7 rather than at carbon to give the desired reduction product 6. However, treatment of 19 with ethanolic sodium hydrosulfide gave the tetrahydrothiofuran 20, which upon treatment with Raney nickel was readily converted to 6. The monobromo derivatives (7 and 8) of the dimethyl compounds were prepared by free-radical addition of hydrogen bromide to the olefin 21. The trans isomer 8 predominated over the cis isomer 7 in a ratio of 7:1.…”

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confidence: 99%

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Bridged polycyclic compounds. LXXXIII. Steric and bromine substituent acceleration in bromination reactions

Cristol¹,

Mueller²,

Macintyre³

et al. 1976

J. Org. Chem.

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Free-radical brominations of a number of bridged compounds (compounds 3-9) have been carried out, with attention paid both to product compositions and to relative reactivities. Each of the compounds had at least one tertiary hydrogen atom at a nonbridgehead position, and reaction occurred exclusively at such positions. A solvent system was devised which scavenged hydrogen bromide rapidly, and competitive brominations were conducted with pairs of compounds. The relative reactivities of the compounds have been rationalized in terms of structural features, and the product compositions have also been discussed. 7 8 B r % -CHJwCHzBr 9 10 Br CH3%=55H3 11 12 CHiBr C H 3 w B r 13 14 1920Cristol, Mueller, Macintyre, and Haltiwanger butene, respectively. When 4 was prepared in this fashion in a steel pressure autoclave, contamination with 5 was observed. This contamination, which was presumably the result of ferric ion catalyzed olefin isomerization, was eliminated by addition of small amounts of ethylenediaminetetraacetic acid and phthalonitrile to coordinate with the iron.2-Methyl-2-butene could not be induced to react with anthracene to give 6. Apparently the extra methyl group provides too much steric hindrance to allow r e a~t i o n .~ As 3, 4, and 5 had been prepared by lithium aluminum hydride reductive displacements on p-toluenesulfonate such a process appeared attractive for 6 as well. To this end, 16, or its epimer, was required. Lithium aluminum hydride reduction of 151° did not proceed well, hut conversion of 15 to 17,j0 followed by LiAlH4 reduction, gave 16 readily 17 CH,OSO,Ph 19 CH, 21 16 18 CH 20 CH3w:H3 22

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Decomposition Rates of Organic Free Radical Initiators

Dixon

1999

The Wiley Database of Polymer Properties

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Steric driving forces in perester decomposition. tert-Butylperoxy di-tert-butylacetate

Cited by 7 publications

References 1 publication

High pressure studies. XV. Effects in aliphatic perester decomposition

High pressure studies. XV. Effects in aliphatic perester decomposition

Bridged polycyclic compounds. LXXXIII. Steric and bromine substituent acceleration in bromination reactions

Decomposition Rates of Organic Free Radical Initiators

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