The camphenehydro (methylcamphenilyl) and isobornyl (bornyl) cations. III. Oxidative decarboxylation of carboxylic acids with lead tetraacetate

The oxidative decarboxylation of exo- and endo-bornane-2-carboxylic acid, exo- and endo-2,3,3- trimethylnorbornane-2-carboxylic acid and a-campholenylcarboxylic acid [3-(2',2',3'-trimethyl- cyclopent-3'-eny1)propanoic acid] with lead tetraacetate in benzene and dimethyl sulphoxide (each containing pyridine) in the presence, and absence, of cupric acetate has been investigated. The mode of formation of almost all the products can be satisfactorily rationalized in terms of the initial generation of radicals. In the case of exo- and endo-bornane-2-carboxylic acid, the derived bornyl radical forms organolead and organocopper derivatives that decompose in three ways: (1) by heterolysis by the direct route to give the equilibrating isobornyl and camphenehydro cations, (2) by a cyclic cis-elimination to give bornylene and (3) by an SNi process to give isobornyl and bornyl acetates. exo- and endo-2,3,3-Trimethylnorbornane-2-carboxylic acid yield the 2,3,3-trimethyl- norborn-2-yl radical which is converted into the equilibrating camphenehydro and isobornyl cations either by one-electron oxidation by lead species or via organolead or organocopper derivatives which undergo heterolysis. Processes involving cyclic cis-elimination and SNi substitution may also operate in the organometallic derivatives derived from the tertiary radical. a-Campholenylcarboxylic acid yields the a-campholenyl radical which, in the absence of cupric acetate, undergoes in the main cyclization to give the 2,3,3-trimethylnorbornyl radical. The resulting mixture of products is similar to that obtained from exo- and endo-2,3,3-trimethylnorbornane-2- carboxylic acid. In the presence of cupric acetate, the a-campholenyl radical is trapped at least to the extent of 50% in benzene and 80% in dimethyl sulphoxide to give the corresponding organo- copper derivative which undergoes a cyclic elimination to give 2,3,3-trimethyl-4-vinylcyclopentene and may undergo heterolysis by the x-route to give the camphenehydro and isobornyl cations. A marked change in the composition of the products on changing the solvent from benzene to dimethyl sulphoxide is observed only in the case of a-campholenylcarboxylic acid in the presence of cupric acetate.

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The mechanism of lead tetraacetate decarboxylation. I. Tertiary carboxylic acids

Australian Journal of Chemistry ◽

10.1071/ch9741673 ◽

1974 ◽

Vol 27 (8) ◽

pp. 1673 ◽

Cited By ~ 12

Author(s):

ALJ Beckwith ◽

RT Cross ◽

GE Gream

Keyword(s):

Acetic Acid ◽

Reaction Mechanism ◽

Carboxylic Acid ◽

Product Distribution ◽

Lead Tetraacetate ◽

Copper Salts ◽

Elimination Process ◽

Initial Generation ◽

Cis And Trans ◽

Lead Species

The reactions of cis- and trans-decalin-9-carboxylic acid, 2,2,3-trimethylbutanoic acid, and adamantane-1-carboxylic acid with lead tetraacetate in benzene and, in some cases, acetic acid have been studied. In each case the nature and distribution of the products is consistent with the hypothesis that the reaction mechanism involves the initial generation of tertiary radicals which are subsequently converted into the related cations either by one-electron oxidation by lead species, or via organolead intermediates which undergo heterolysis. The change in product distribution which occurs when the reactions are conducted in the presence of copper salts indicates that tertiary radicals react rapidly with cupric species to afford organocopper intermediates from which olefins are derived by a cis-elimination process, and acetates by SNi or heterolytic mechanisms.

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The mechanism of lead tetraacetate decarboxylation. II. 2,3,3-Trimethylbutanoic and Adamantane-2-carboxylic acids

Australian Journal of Chemistry ◽

10.1071/ch9741693 ◽

1974 ◽

Vol 27 (8) ◽

pp. 1693 ◽

Cited By ~ 6

Author(s):

ALJ Beckwith ◽

RT Cross ◽

GE Gream

Keyword(s):

Acetic Acid ◽

Carboxylic Acid ◽

Carboxylic Acids ◽

Major Product ◽

Lead Tetraacetate ◽

Oxidative Decarboxylation ◽

Catalysed Reaction

Oxidative decarboxylation of 2,3,3-trimethylbutanoic acid with lead tetraacetate in benzene or acetic acid affords mainly 3,3-dimethylbut-2-yl acetate; the major product from the cupric salt catalysed reaction is 3,3-dimethylbut-1-ene. The low yields detected of rearrangement products provide evidence for the intermediacy of organolead and organocopper compounds which decompose by SNi displacement or cyclic cis-elimination. Other reactions discussed are oxidative decarboxylation of adamantane-2-carboxylic acid, deamination of 3,3-dimethylbut-2-ylamine, and thermolysis of bis(2,3,3-trimethylbutanoyl) peroxide and of t-butyl adamantane-2-percarboxylate. A reinterpretation of previous results on the oxidative decarboxylation of exo- and endo-nor- bornane-2-carboxylic acid with lead tetraacetate is presented.

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The Formation of Carbonium Ions by Oxidative Decarboxylation of Carboxylic Acids with Lead Tetraacetate

Journal of the American Chemical Society ◽

10.1021/ja00885a013 ◽

1963 ◽

Vol 85 (2) ◽

pp. 165-169 ◽

Cited By ~ 62

Author(s):

E. J. Corey ◽

J. Casanova

Keyword(s):

Carboxylic Acids ◽

Lead Tetraacetate ◽

Oxidative Decarboxylation ◽

Carbonium Ions

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Improved synthesis of anti-sesquinorbornene

Canadian Journal of Chemistry ◽

10.1139/v84-315 ◽

1984 ◽

Vol 62 (9) ◽

pp. 1840-1844 ◽

Cited By ~ 5

Author(s):

Karl R. Kopecky ◽

Alan J. Miller

Keyword(s):

Acetic Acid ◽

Sulfuric Acid ◽

Carboxylic Acid ◽

Lead Tetraacetate ◽

Carboxyl Group ◽

Silver Acetate ◽

Benzenesulfonyl Chloride ◽

Methoxide Ion ◽

Hydrolysis Of ◽

Monomethyl Ester

Treatment of methyl hydrogen decahydro-1,4:5,8-exo,endo-dimethanonaphthalene-4a,8a-dicarboxylate with lead tetraacetate in benzene – acetic acid replaces the carboxyl group by an acetoxy group. Hydrolysis of this product with 25% sulfuric acid at 130 °C forms 8a-hydroxydecahydro-1,4:5,8-exo,endo-dimethanonaphthalene-4a-carboxylic acid 10. The reaction between 10 and benzenesulfonyl chloride in pyridine containing triethylamine at 95 °C produces anti-sesquinorbornene 1 in 34% yield. In the absence of triethylamine 1 is converted to the hydrochloride. The iodohydroperoxide of 1 is converted by silver acetate at 0 °C to the diketone in a luminescent reaction. The 1,2-dioxetane could not be isolated. Decahydro-1,4:5,8-exo,exo-dimethanonaphthalene-4a,8a-dicarboxylic anhydride is converted slowly by methoxide ion in methanol at 150 °C to the monomethyl ester which then undergoes demethylation. The isomeric exo,endo anhydride undergoes reaction readily with methoxide ion at 80 °C.

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THE LOCATION OF THE XANTHATE GROUPS IN PARTLY SUBSTITUTED CELLULOSE XANTHATES

Canadian Journal of Chemistry ◽

10.1139/v57-200 ◽

1957 ◽

Vol 35 (12) ◽

pp. 1522-1533 ◽

Cited By ~ 6

Author(s):

E. P. Swan ◽

C. B. Purves

Keyword(s):

Cellulose Acetate ◽

Chlorine Dioxide ◽

Methyl Esters ◽

Lead Tetraacetate ◽

Degree Of Substitution ◽

Hydroxyl Groups ◽

Primary Position ◽

Standard Methods ◽

The Third ◽

Almost All

Cellulose sodium xanthates of degree of substitution (D.S.) 0.4 to 0.66 were methylated to xanthate S-methyl esters which were then acetylated completely, the final xanthate D.S. remaining close to the original value. Dexanthation with aqueous chlorine dioxide near pH 4.5 and −5° removed almost all of the S-methyl xanthate groups, but the loss of a few acetyl groups from, and the retention of 1 to 2% of sulphur in, the resulting cellulose acetate could not be avoided. The original xanthate groups were presumably represented in this acetate as unsubstituted hydroxyl groups, and these were located by standard methods involving tosylation–iodination, tritylation, and oxidations with lead tetraacetate. Xanthate groups appeared to occupy the third and sixth, but not the second, position in the cellulose, and 53 to 61% of the substituent was in the sixth or primary position; one sample of viscose was "ripened" before the cellulose sodium xanthate was isolated, and the value was 81%. The results were of a preliminary nature, because severe technical difficulties reduced their reliability.

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Studies of Strained Ring Systems: Cyclopropa[1]Phenanthrenes

10.26686/wgtn.16945345.v1 ◽

2021 ◽

Author(s):

◽

Barry Roy Dent

Keyword(s):

Carboxylic Acid ◽

Model Compound ◽

Structural Type ◽

Ring System ◽

Convincing Evidence ◽

Conclusive Evidence ◽

Oxidative Decarboxylation ◽

Fluoride Ion ◽

Allyl Cation ◽

Dichloro Derivative

<p>The aim of the present study has been the synthesis of 1H-cyclo-Propa[1]phenanthrene (16a) and its derivatives, the sole remaining unknown structural type of the cycloproparenes. Established procedures for cycloproparene synthesis are not readily adaptable to this ring system, and routes based upon new bridge-head-substituted 1a,9b-dihydrocyclopropa[1]phenanthrenes are examined. 1, 1-Dichloro-1a-phenylseleno-1a, 9b-dihydrocyclopropa [1] phenanthrene (73) is prepared by the addition of dichlorocarbene to the corresponding phenanthrenyl selenide (72). syn-Selenoxide elimination of PhSeOH from the derived selenoxide (74) gives 1,1-dichloro-1H-cyclopropa[1]phenanthrene (76) which is intercepted by methanolysis. Labelling studies provide convincing evidence for the intermediacy of the 1H-cycloproparene. The viability of an oxidative decarboxylation route to 1,1-dialkyl-1H-cyclopropa[1]phenanthrenes is investigated for the model compound 7,7-dimethylbicyclo[4.1.0]hept-3-ene-1-carboxylic acid (122). A product of formal cyclopropyl-allyl cation rearrangement, is isolated. 1a-Methylseleno-1a,9b-dihydrocyclopropa[1]phenanthrenes (174) is prepared by the unprecedented addition of methylselenide anion to 1aH-cyclopropa[1]phenanthrene (63) (generated by a new route involving the fluoride ion-promoted elimination of the elements of chlorotrimethylsilane from the isomeric 1-chloro-1a-trimethylsilyl-1a, 9b-dihydrocyclopropa[1]phenanthrenes (170) and (171)). Treatment of the drived dimethylselenonium tetra-fluoroborate (179) with base in the presence of furan gives the endo- and exo-furan cycloadducts (180) and (181) of 1H-cyclopropa[1]phenanthrene (16a). The results presented herein provide the first conclusive evidence for the existence of the 1H-cyclopropa[1]phenanthrene ring system, both as the parent hydrocarbon (16a) and the 1,1-dichloro-derivative(76).</p>

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Oxidative decarboxylation of the 3-methyl-2-carboxynorbornanes with lead tetraacetate

Canadian Journal of Chemistry ◽

10.1139/v76-172 ◽

1976 ◽

Vol 54 (8) ◽

pp. 1222-1225 ◽

Cited By ~ 3

Author(s):

J. B. Stothers ◽

K. C. Teo

Keyword(s):

Carboxylic Acids ◽

Lead Tetraacetate ◽

Starting Material ◽

Oxidative Decarboxylation ◽

Methyl Group

The mixtures of isomeric acetates produced by oxidative decarboxylation of the four 3-methyl-norbornane-2-carboxylic acids with lead tetraacetate in benzene have been characterized. The composition of these products depends primarily on the configuration of the methyl group in the starting material. The results are compared with those found for the Pb(OAc)4 decarboxylation of the norbornane-, bornane-, and 2,3,3-trimethylnorbornane-2-carboxylic acids. The formation of the products is interpreted in terms of competitive cationic and SNi substitution.

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A local proton source from carboxylic acid functionalized metal porphyrins for enhanced electrocatalytic CO2 reduction

New Journal of Chemistry ◽

10.1039/d0nj02900a ◽

2020 ◽

Vol 44 (37) ◽

pp. 16062-16068

Author(s):

Yiwei Zhou ◽

Yunheng Xiao ◽

Jian Zhao

Keyword(s):

Carboxylic Acid ◽

Benzoic Acid ◽

Co2 Reduction ◽

Proton Donor ◽

Propanoic Acid ◽

Metal Porphyrins ◽

Proton Source

Metal tetraphenylporphyrin modified through the introduction of propanoic acid into the phenyl groups as a local proton donor exhibits higher CO2 electrocatalytic conversion to CO than benzoic acid.

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