Stereochemistry of Allylic Rearrangements. XIV. Ion-Pair Return Associated with the Solvolysis of <i>cis</i>-5-Methyl-2-cyclohexenyl <i>p</i>-Nitrobenzoate in Aqueous Acetone

Goering, Harlan L.; Doi, Joyce Takahashi; McMichael, Kirk D.

doi:10.1021/ja01064a010

Cited by 20 publications

(3 citation statements)

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“…This model indicates that bond formation is not the rate-determining process. If the bond-forming step, k_i, were the rate-limiting step, i.e., (krac + k2) » k-i, then "/ "^"^(krac+k^( 17) These qualitative conclusions regarding the epimerization process are not altered by allowing the intermediates to exchange their waters of solvation with the surrounding medium and/or increasing the number of water molecules within the solvation sphere.…”

Section: Discussionmentioning

confidence: 99%

Oxygen exchange as a function of epimerization of 15(R)- and 15(S)-methylprostaglandin E2. Evidence for asymmetric carbonium ion intermediates

Merritt¹,

Bronson²,

Baczynskyj³

et al. 1980

J. Am. Chem. Soc.

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The rate of oxygen exchange of each epimer as a function of epimerization of 15(i?)-methylprostaglandin E2 (R) and 15(S)-methylprostaglandin E2 (S) (tertiary alcohols) in 180-enriched water has been determined by LC and GC-MS methods. The relative rates indicate that exchange of the C-15 hydroxyl group is more rapid than the change in configuration at C-15. These data are consistent with a mechanism for epimerization in which the initially formed carbonium ion formally retains the configuration of starting material. A significant percentage of the initially formed epimerized product does not exchange with the ,80-enriched water. This result indicates that, in some cases, the departing water molecule ultimately bonds the carbonium ion from the opposite face. A reaction scheme is proposed in which the waters of solvation exchange with the departing water more rapidly than the initially formed carbonium ion epimerizes.

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Section: Discussionmentioning

confidence: 99%

Oxygen exchange as a function of epimerization of 15(R)- and 15(S)-methylprostaglandin E2. Evidence for asymmetric carbonium ion intermediates

Merritt¹,

Bronson²,

Baczynskyj³

et al. 1980

J. Am. Chem. Soc.

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“…Goering, et al (11,12) found that cis-and trans-5-methyl-2-cyclohexenyl p-nitrobenzoates undergo solvolysis and internal return when reacted with 80% aqueous acetone. The reactions proceed through a symmetric bridged ion-pair ( Fig.…”

Section: Solvolysis Of Several Noncyclic Allylic Compounds In Alcoholmentioning

confidence: 99%

Solvolysis of cis-pinocarvyl p-bromobenzenesulfonate and related esters

Gruenewald¹,

Johnson²

1967

J. Org. Chem.

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Brosylate 45 2-Methylenecyclohexyl Brosylate 47 Stability of Solvolysis Products 47 Acetolysis of cis-Pinocarvyl Brosylate 48 Solvolysis of Saturated Brosylates 48 Alkaline Methanolysis 48 Isopinocamphyl Brosylate 48 trans-2-Methylcyclohexyl Brosylate 50 Solvolysis of Unsaturated p-Nitrobenzoates Alkaline Methanolysis of cis-Pinocarvyl, trans-Pinocarvyl, and 2-Methylenecyclohexyl p-Nitrobenzoate Attempted Hydrolysis of cis-Pinocarvyl, trans-Pinocarvyl, and 2-Methylenecyclohexyl p-Nitrobenzoate DISCUSSION cis-Pinocarvyl Brosylate Solvolysis Mechanisms Carbon-Oxygen Cleavage and Allylic Rearrangement Lyate Ion Effect Salt Effect Solvent Effect Proposed Solvolysis Mechanisms Effect of cis-Pinocarvyl Structure on-Mechanism and Rate of Brosylate Solvolysis Effect of the Isopropylidene Bridge 62 Effect of Unsaturation 65 Effect of Leaving Group on Mechanism of Solvolysis of cis-Pinocarvyl and Related Esters Alkaline Methanolysis of Unsaturated p-Nitrobenzoates Hydrolysis of Unsaturated p-Nitrobenzoates

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“…The example of internal return which follows is neither the simplest nor the first to be studied, but it is an elegant one, and illustrates the use of an ingenious combination of kinetic, stereochemical, and labeling techniques to probe a very subtle problem. The reaction in question is the solvolysis of the cis allylic ester XII in 90% aqueous acetone (19). 0…”

mentioning

confidence: 99%