Stereospecific introduction of double bounds via thermolysis of .beta.-lactones

Adam, Waldemar; Baeza, Jaime; Liu, Juchao

doi:10.1021/ja00761a036

Cited by 195 publications

(69 citation statements)

References 2 publications

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“…Conceptually,¯-lactones can be prepared by activation of either the hydroxyl or carboxyl groups of monoesters Scheme 7. Reagents and conditions: (a) D1AD, TPP, THF, room temperature, 3 h. [16][17][18][19][20][21][22]. Among the different methods of lactonization of¯-hydroxyacids described in the literature, we chosen the Mitsunobu reaction [23,24].…”

Section: Resultsmentioning

confidence: 99%

Synthesis of new α, α′, β-trisubstituted β-lactones as monomers for hydrolyzable polyesters

Barbaud¹,

Abdillah²,

Faÿ³

et al. 2003

Designed Monomers and Polymers

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Abstract-Novel ®,® 0 ,¯-trisubstituted¯-lactones have been prepared by a concise and ef cient synthesis in ve steps from commercial racemic diethyl oxalpropionate. These lactones with different lateral groups can be polymerized or co-polymerized for obtaining polyesters with high molecular weight. Chemical modi cation of these functionalized hydrolyzable polymers will be used to adjust their properties to the selected temporary applications.

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Section: Resultsmentioning

confidence: 99%

Synthesis of new α, α′, β-trisubstituted β-lactones as monomers for hydrolyzable polyesters

Barbaud¹,

Abdillah²,

Faÿ³

et al. 2003

Designed Monomers and Polymers

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“…preparation of tetrasubstituted ethylenes from P-hydroxy,acids has been reported (5). In fact the conversion is straightforward.…”

Section: Resultsmentioning

confidence: 99%

“…']dodecane-2, 7-dione, 1. 5 Method A A solution of 20 mg 1 in 10 mL pentane at -70°C was treated with ozone. The residue remaining on evaporation of the pentane was suspended 10 mL ethanol together with 100 mg palladium on charcoal.…”

Section: Conversion Of 11 Tomentioning

confidence: 99%

Improved synthesis of anti-sesquinorbornene

Kopecky¹,

Miller²

1984

Can. J. Chem.

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, 1840 (1984). Treatment of methyl hydrogen decahydro-l,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,exodimethanonaphthalene-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. isoler le dioxitane-1,2. A 150°C, I'ion methylate dans le mithanol transforme lentement I'anhydride de I'acide dicahydro-1,4:5,8 dimithano-exo,exo naphtalenedicarboxylique-4a,8a en ester monomithyllique qui subit alors une demkthylation. L'anhydridre isomere exo,endo reagit facilement avec l'ion methylate a 80°C.[Traduit par le journal] Introduction It was concluded from the study (1) of a series of mono-, di-, and tricyclic-l,2-dioxetanes that C-C bond rotation was not required to accompany 0-0 bond rupture (2) in the thermolysis of these compounds. A study of the thermolysis of the dioxetane 2 of anti-sesquinorbornene 1 (3) might provide a further test of this conclusion. Examination of molecular models indicates that the perhydro-1,4 : 5,8-dimethanonaphthalene skeleton is very rigid. There would be no rotation about the C,,-C8, bond in 3. The present paper reports an improved synthesis of 1, some reactions of precursors to 1, and the apparent instability of 2.

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“…The experiments described concern syntheses [46][47][48][49][50][51][52][53][54][55][56][57][58][59] and spectral properties [7,37,60]; the above-mentioned argentation was studied kinetically [7]. The theoretical approach includes calculations oriented to the electron properties [37] and an effect of α-substitution on the stability of the respective carbocation [40].…”

mentioning

confidence: 99%

Kinetics and Mechanism of Acetoxymercuration and Acid-Catalysed Hydration of α-Alkylstyrenes

Svoboda

Pelcová

Nevěčná

et al. 2005

IJMS

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Nine α-alkylstyrenes carrying the following substituents have been synthesised : methyl, ethyl, propyl, butyl, pentyl, isobutyl, isopropyl, sec-butyl and tert-butyl. Kinetics has been measured for the reaction of these compounds with mercuric acetate in anhydrous acetic acid at 25 °C. The rate constants are very sensitive to inductive effects (ρ I = -49.5 in AISE theory) and steric effects (ψ = -1.59 according to Charton). These results support the presumed existence of an intermediate with an asymmetrically bound acetylmercuric cation to carbon atoms of the vinyl group of styrene. The kinetics of an acid-catalysed hydration of the above-mentioned α-alkylstyrenes were also measured in aqueous sulphuric acid at 25 °C. The derivatives exhibited kinetically a consecutive isomerisation reaction giving the more stable substituted styrenes. The values of the slope m ‡ m* of the dependence upon the excess acidity function (X) were evaluated, and exceptionally low values were found for the butyl and pentyl substituents (1.02 and 0.73, respectively), while on the other hand tert-butyl showed an exceptionally high value (3.28). On the basis of the facts, a mechanism has been suggested for the acid-catalysed hydration, involving the reaction of31 a relatively stable and sterically hindered carbocation with water as the rate-limiting step of the reaction.

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Stereospecific introduction of double bounds via thermolysis of .beta.-lactones

Cited by 195 publications

References 2 publications

Synthesis of new α, α′, β-trisubstituted β-lactones as monomers for hydrolyzable polyesters

Synthesis of new α, α′, β-trisubstituted β-lactones as monomers for hydrolyzable polyesters

Improved synthesis of anti-sesquinorbornene

Kinetics and Mechanism of Acetoxymercuration and Acid-Catalysed Hydration of α-Alkylstyrenes

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