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Reaction id: 0501011027_04, verified by Personal Chemistry ©
2d
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Ethylene glycol
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3d
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Yield: 74% Time: 360s Temperature: 250 °C
Chemicals
| Name |
MW [g/mol] |
Density [g/ml] |
Amount [mmol] |
Mass/Volume |
| Substrate 1 |
379.957 |
1.000 |
0.500 |
189.978 µl |
| Ethylene glycol |
62.068 |
1.113 |
35.864 |
2000.000 µl |
| Product 1 |
379.957 |
1.000 |
0.000 |
0.000 µl |
Keywords
Heterocyclisation, Radical, Ring closure
Comments
Synthesis: Ethylene glycol was found to be the best solvent for this radical group transfer reaction after isopropanol, NMP, diethylene glycol dimethyl ether and water were also tried. Using this method, yields were similar to those obtained with conventional heating, but in that case photolysis in refluxing benzene and substantial amounts of hexabutylditin were required. The conventional reaction, however, gives better diastereoselectivity. In this reaction, the endo/exo ratio was 1/1.8. When attempted in water, this reaction gave less than 10% yield.
Work-up and purification: After heating, the reaction mixture was extracted with diethyl ether. The ether fraction was then washed with water and dried over MgSO4. The product was purified by flash column chromatography (silica eluted with pentane and 3-10% ethyl acetate).
Characterisation: By IR, HRMS, 1H and 13C NMR.
Instrument Settings
Absorption level: Normal
Pre-stirring time: 0s
References
Ericsson, C.; Engman, L. J. Org. Chem. 2004, 15, 5143-5146
Analysis
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