Chemistry of enolates. V. Solvent effects on the activity of carbanions

Zook, Harry D.; Russo, Thomas J.; Ferrand, E. F.; Stotz, Diethard

doi:10.1021/jo01270a012

Cited by 47 publications

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“…These products have been formulated as dimers of 3phenylindenone involving cyclobutane rings. [4][5][6] In agreement with these investigations, the action of sulfuric acid on ethyl 3,3-diphenyl-3-hydroxypropanoate gave isomeric ketones melting at 255-259°( I) and 224-226°( II). The nmr spectra of these two compounds were not in agreement with the truxone structures postulated.4'5 6Isomer I gave a singlet at 3.88 (1 H), half of an AB quartet at 3.84 (J = 19 cps) (1 H), and the other half at 2.58 (J = 19 cps) (1 H).…”

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confidence: 54%

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Chemistry of Enolates .7. Kinetics and Orientation in Dimethyl Sulfoxide - Relative Nucleophilicities of Enolates

Zook¹,

Miller²

1971

J. Org. Chem.

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confidence: 54%

“…The preparations of ketones have been described. 4 Purity was checked by glpc analysis on a 5 ft X 0.3 mm column of phenylsilicone on Gas Chrom Z.…”

Section: Methodsmentioning

confidence: 99%

Chemistry of Enolates .7. Kinetics and Orientation in Dimethyl Sulfoxide - Relative Nucleophilicities of Enolates

Zook¹,

Miller²

1971

J. Org. Chem.

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“…Proton assignments were made by following conventional nmr rules and by deuterium labeling as indicated in Table I. When A was plotted against the Hammett u values,7a Brown's a+ constants,7b and the normal substituent constants, u O ,~ for the substituents of the various three-memljered ring ketones, good linear relationships were obtained as shown by the correlation coefficients in Table 11. (4) To whom inquiries should be addressed a t Georgia State University, Atlanta, Ga. 30303. W. Boykin, Jr., A.…”

Section: Resultsmentioning

confidence: 99%

Solvent effects in nuclear magnetic resonance spectroscopy. II. Transmission of substituent effects by three-membered rings

Boykin¹,

Turner²,

Lutz³

et al. 1971

J. Org. Chem.

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1107The nmr spectra of a series of trans-1-(substituted phenyl)-2-benzoyl-3,3-dideuteriocyclopropanes, trans-2-(substituted phenyl)-3-benzoyloxiranes, and trans-and cis-l-cyclohexyl-2-(substituted phenyl)-3-bemzoylaziridines have been determined in deuteriochloroform and in benzene. The difference in chemical shifts in the two solvents, A = G C D C~~ -6 c 6~e , has been correlated with substituent parameters, u, uo, u+, and the Swain field and resonance parameters. Generally, good correlations were obtained using u and u0 constants; however, correlations using F and R were usually better. Comparisons of p values obtained using u constants indicate that the order of efficiency of transmission of substituent effects for the ring systems studied is cyclopropane N oxirane > aziridine.A number of reports have appeared which compare the transmission of electronic effects by the ethylene group, the cyclopropane ring, and the dimethylene group.5 Only recently have reparts appeared which include the small-ring heterocyclic systems, oxiranese and aziridines,ea in these comparisons. As a continuation of our earlier investigations' of nmr solvent effects on three-membered ring ketones, we have studied the effect of substituents in these systems in an attempt to compare the relative abilities of various three-membered rings to transmit substituent effects. ResultsThe nmr spectra of substituted phenylbenzoylcyclopropanes, -oxiranes, and -aziridines have been determined in deuteriochloroform and in benzene. Table I contains the proton chemical shift data for these threemembered ring ketones. The proton resonance values are expressed in hertz relative to tetramethylsilane (TMS) as an internal standard, and A is defined as SCDCI~ -S C~H~. Proton assignments were made by following conventional nmr rules and by deuterium labeling as indicated in Table I. When A was plotted against the Hammett u values,7a Brown's a+ constants,7b and the normal substituent constants, u O ,~ for the substituents of the various three-memljered ring ketones, good linear relationships were obtained as shown by the correlation coefficients in Table 11. Plots using u constants are recorded in Figure 1 and the slopes p as determined by the method (1) For part I, see of least squares9& are given in Table 11. The statistical treatments were carried out with the aid of a computer program.9b Table I11 contains the results of correlation of the nmr data with the Swain-Lupton expression. lo The l-phenyl-2-benzoyl-3,3-dideuteriocyclopropanes were prepared by the synthetic method reported by Coreylla using dimethyloxosulfonium methylide-ds and substituted chalcones. I n all cases, except for the reaction of 3,4-dichlorochalcone, substituted chalcones reacted at 55" with the ylide-ds to give the corresponding 3,3-dideuteriocyclopropane. The 3,4-dichlorochalcone gave l-(3,4-dichloropheny1)-2-benzoyl-2,3,3trideuteriocyclopropane under the above conditions as demonstrated by its nmr spectrum and by the basecatalyzed exchange of the 2-deuterium atom in refluxing eth...

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“…Significantly, the degree of C-versus O-alkylation is modified by the reaction conditions, as well as by the choice of enolate ion. Thus, the enolate formed by the sterically hindered diphenylacetophenone has been found to react with methyl iodide to yield 50% of the O-methylated product in DMSO [16,17]. DMSO with a soft sulfur center would not coordinate to the same degree with the oxygen as hard as metal cations do, and O-alkylation would be favored.…”

Section: Introductionmentioning

confidence: 99%

Synthesis Of 1,8‐dioxa‐dibenzo[e,h]azulenese

Pešić

Landek

Merćaep

et al. 2006

Journal of Heterocyclic Chem

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A novel synthetic route to 2‐methyl‐1,8‐dioxa‐dibenzo[e,h]azulenes [1] via cyclisation of the corresponding 1,4‐dicarbonyl compound is described. 1,4‐Dicarbonyl compounds were synthesized by the alkylation reaction of the 11H‐dibenzo[b,f]oxepine‐10‐one while analogous alkylation of 11H‐dibenzo[b,f]thiepine‐10‐one resulted in formation of O‐alkylated products. Selective oxidation of 2‐methyl group afforded 1,8‐dioxa‐dibenzo[e,h]azulenes with formyl and hydroxymethyl functionality at C(2) position.

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Chemistry of enolates. V. Solvent effects on the activity of carbanions

Cited by 47 publications

References 0 publications

Chemistry of Enolates .7. Kinetics and Orientation in Dimethyl Sulfoxide - Relative Nucleophilicities of Enolates

Chemistry of Enolates .7. Kinetics and Orientation in Dimethyl Sulfoxide - Relative Nucleophilicities of Enolates

Solvent effects in nuclear magnetic resonance spectroscopy. II. Transmission of substituent effects by three-membered rings

Synthesis Of 1,8‐dioxa‐dibenzo[e,h]azulenese

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