- Development of a one-pot method for the homologation of aldehydes to carboxylic acids
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A highly efficient method is described for the one-carbon homologation of aldehydes to carboxylic acid derivatives employing the reaction of a 1,1-bis-dimethylphosphonate derivative with the aldehyde and controlled acid hydrolysis of the derived α-phosphonoenamine intermediate.
- McNulty, James,Das, Priyabrata
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experimental part
p. 7794 - 7800
(2009/12/26)
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- An improved synthesis of α-phosphonoenamines based on a modified Peterson olefination
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An efficient, stereoselective method for the synthesis of α-phosphonoenamines based on a modified Peterson olefination is described. The carbanion derived from isolatable intermediate 2 reacts with aromatic or aliphatic aldehydes selectively eliminating in Peterson fashion to deliver functionally rich α-phosphonoenamines 3. The synthetic utility of these enamines is demonstrated by their hydrolysis yielding the homologous carboxylic acids in good yield.
- McNulty, James,Das, Priyabrata,Gosciniak, Don
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p. 281 - 285
(2008/03/30)
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- α-SUBSTITUIERTE PHOSPHONATE 38. 1-DIMETHYLAMINO-1-CYANO-METHANPHOSPHONSAEUREDIETHYLESTER, EIN NEUES EDUKT ZUR DARSTELLUNG VON CARBONSAEUREN, 1-CYANOENAMINEN UND HOMOENOLATEN.
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Alkylation of 1-dimethylamino-1-cyanomethanephosphonic acid diethyl ester (8), easily obtainable from diethyl phosphite and the O,N-acetal 9, yields 1-alkyl derivatives 14.Elimination of HCN converts 14 into 1-phosphonoenamines 6.Carbonyl compounds react with 8 to give 1-cyanoenamines 15 which may be hydrolyzed to form the homologous carboxylic acid.Alternatively, deprotonation of 15 yields the homoenolate anions 17 which can be alkylated or hydroxyalkylated, permitting chain extension of carbonyl compounds through introduction of an α-carboxyl and a β-alkyl group.Acid catalyzed hydrolysis of 8 results in the cleavage of the P-C bond, leading to the corresponding α-dimethylamino alkanoic acids.A phosphonic acid 11 can be obtained from 8 by application of the silylester method.An unambigous assignment of E/Z-isomers of cyanoenamines 15 has been derived from 13C-NMR spectroscopy.
- Costisella, Burkhard,Gross, Hans
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p. 139 - 145
(2007/10/02)
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- α-SUBSTITUIERTE PHOSPHONATE-36 α-PHOSPHONOENAMINE UND ACYLPHOSPHONATE DURCH HORNER-OLEFINIERUNG
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Phosphonoenamines are formed by Horner-Olefination of N-substituted aminomethane-bis-phosphonic acid esters.These exist, depending on N-substitution, carbonyl compound, and condition of the reaction as pure E- or Z-isomeres resp. as E,Z-mixture.The stereochemistry unambiguously could be derived from the 1H- resp. 13C-NMR-spectra.Mild hydrolysis of the phosphonoenamines yields acylphosphonates; 31P-NMR-data shows, that these exist as a mixture of keto-enol-form.The enol-form of this products could be isolated in crystalline form.Phenylacetylphosphonate, unambiguously synthesized from phenylacetylchloride and triethylphosphite also exist as a mixture of the keto-enol-form.
- Costisella, B.,Keitel, I.,Gross, H.
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p. 1227 - 1232
(2007/10/02)
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