Organofluorine compounds and fluorinating agents Part 17: Sonochemical-forced preparation of perfluoroalkanals and their use for non-conventional acetalations of carbohydrates
| Autor: | Michael Frank, Alexey O. Miller, Ralf Miethchen, Dietmar Peters, C. Zur |
|---|---|
| Rok vydání: | 1997 |
| Předmět: |
chemistry.chemical_classification
Sonication Organic Chemistry medicine.disease Biochemistry Phosphonate Aldehyde Inorganic Chemistry chemistry.chemical_compound chemistry medicine Environmental Chemistry Hemiacetal Monosaccharide Organic chemistry Epimer Organofluorine compounds Dehydration Physical and Theoretical Chemistry |
| Zdroj: | Journal of Fluorine Chemistry. 82:33-38 |
| ISSN: | 0022-1139 |
| DOI: | 10.1016/s0022-1139(96)03551-8 |
| Popis: | The homologous 1-iodo-perfluoroalkanes 1a-1c and α,ω-dibromo-perfluoroalkanes 4a, 4b were carbonylated with DMF in the presence of Al/SnCl 2 Al/PbBr 2 under sonication in a short reaction time. The hydrated aldehydes 2a-2c and 5a, 5b respectively were obtained in good yields allowing dehydration to 3a-3c and 6a, 6b . Some of the fluorinated aldehydes were selected as substrates in a Wittig-Horner olefination assisted by ultrasound and in non-conventional acetalations of methyl α- l -rhamnopyranoside ( 9 ). Thus, ( E )-1-perfluorooctyl-2-phenylsulphonyl-ethene ( 8 ) was prepared from 3c and the phosphonate 7 by Wittig-Horner synthesis. Acetalations of 9 were carried out with the aldehydes ( 3a, 3b, 6a ), hydrated aldehydes ( 2a, 2b ), and the aldehyde hemiacetal 12 respectively, in the presence of dicyclohexylcarbodiimide (DCC). In all cases, a selective epimerization was observed at the C-atom 3 of the monosaccharide, i.e. polyfluoroalkylidenated 6-deoxy-α- l -altropyranosides 10,11,13 , and 14 were obtained. |
| Databáze: | OpenAIRE |
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