反应详情

To 220 mL pentane in a 500 mL photochemical reactor was added 14.32 g (43.9 mmol) di[(5-ethyl-2-vinyl-[1,3]dioxan-5-yl)methyl]ether from the previous step. The solution was refluxed vigorously for 20 minutes to degas it, then 115 μL (171 μg, 0.87 μmol, 0.2 mol %) iron pentacarbonyl was added, and the solution refluxed for an additional 20 minutes. The resulting solution was irradiated for one hour, by when NMR showed no vinyl signals. After cooling to room temperature and the addition of 0.5 mL triethylamine, the solution was sparged with dry air for 4 hours. The pentane was removed by evaporation under reduced pressure, and the residual oil was distilled in a Kugelrohr apparatus (pot temperature 220° C., pressure 1-3 mbar) to give 9.04 g (63% yield) of di[(5-ethyl-2-ethylidene-[1,3]dioxan-5-yl)methyl]ether, 3, as a colorless oil. The identity of the product was confirmed by 1H NMR and mass spectra (observed: 363, 345, calculated for C18H35O7 (M+2H2O+H+): 363; calculated for C18H33O6 (M+H2O+H+): 345).

1. temperatureThe solution was refluxed vigorously for 20 minutes
2. customto degas it
3. temperaturethe solution refluxed for an additional 20 minutes
4. customThe resulting solution was irradiated for one hour, by when NMR
5. customthe solution was sparged
6. customwith dry air for 4 hours
7. customThe pentane was removed by evaporation under reduced pressure
8. distillationthe residual oil was distilled in a Kugelrohr apparatus (pot temperature 220° C., pressure 1-3 mbar)