Sodium dithionite initiated addition of 1-bromo-1-chloro-2,2,2-trifluoroethane to β-pinene
| Autor: | Jolanta Ignatowska, Krystyna Piasecka-Maciejewska, Wojciech Dmowski |
|---|---|
| Rok vydání: | 2004 |
| Předmět: |
chemistry.chemical_classification
Double bond Organic Chemistry Cyclohexene Trifluoroethane Biochemistry Medicinal chemistry law.invention Inorganic Chemistry Sodium dithionite chemistry.chemical_compound chemistry law Pyridine Dehydrohalogenation Environmental Chemistry Organic chemistry Physical and Theoretical Chemistry Walden inversion Isopropyl |
| Zdroj: | Journal of Fluorine Chemistry. 125:1147-1151 |
| ISSN: | 0022-1139 |
| DOI: | 10.1016/j.jfluchem.2004.03.001 |
| Popis: | Sodium dithionite effectively promotes the addition of 1-bromo-1-chloro-2,2,2-trifluoroethane to the exocyclic double bond of β-pinene. The reaction proceeded in an MeCN/H 2 O system to give almost quantitatively a 1:1 mixture of diastereoisomers of 4-(2-bromoisopropyl)-1-(2-chloro-3,3,3-trifluoropropyl)-cyclohexene ( 1 ). Dehydrobromination of 1 with pyridine gave a mixture of regioisomeric dienes 2 and 3 , while treatment with DBU at elevated temperature resulted in total dehydrohalogenation to give trienes 4 and 5 . Reduction of 1 with Bu 3 SnH gave 1-(2-chloro-3,3,3-trifluoropropyl)-4-(isopropyl)cyclohexene ( 6 ) which on dehydrochlorination with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) afforded conjugated diene, 4-isopropyl-1-( trans -3,3,3-trifluoropropenyl)-cyclohexene ( 7 ), with 50% overall yield. All the transformations proceeded with the retention of configuration at the carbon atom C-4 and the final compound 7 exhibited high optical activity. |
| Databáze: | OpenAIRE |
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