反应详情

To a round bottom flask containing methyl 3′,4′-dihydro-1′H-spiro[[1,3]dioxolane-2,2′-naphthalene]-8′-carboxylate (19-2) (1.88 g, 7.57 mmol) was added anhydrous THF (15 ml). The reaction mixture was then cooled to 0 C (ice water bath) while stirring under N2. Then added DIBAL-H (24 mL, 24.00 mmol) dropwise over 10 minutes with stirring. Stirred at 0 C for 10 minutes, then permitted to warm to room temperature. Followed by LC/MS. Stirred overnight at room temperature, noticed there was still some starting material so cooled back to 0 C, then added additional DIBAL-H (19 mL, 19.00 mmol) & after 10 minutes warmed to room temperature. The reaction mixture was cooled to 0 C (ice water bath), then quenched by slow dropwise addition of saturated Rochelle's Salt (Na+/K+ Tartrate) (lots of bubbling so add slowly), then stirred for an hour to help break up/solubilize the emulsion; then suspended in EtOAc, filtered emulsion (gooey material, very little desired product by LC/MS); organics separated, then washed with saturated Rochelle's salt again then washed with saturated NH4Cl, then with saturated NaHCO3, then H2O, then brine; organics dried over sodium sulfate, filtered & concentrated. Purification by silica gel chromatography (30-100% EtOAc/Hex; 80 g ISCO); desired fractions concentrated to yield (3′,4′-dihydro-1′H-spiro[[1,3]dioxolane-2,2′-naphthalen]-8′-yl)methanol (19-3). HRMS [M+Na] calculated; 243.0992, observed; 243.0990.

1. stirringStirred at 0 C for 10 minutes
2. stirringStirred overnight at room temperature
3. temperatureso cooled back to 0 C
4. temperatureafter 10 minutes warmed to room temperature
5. customquenched by slow dropwise addition of saturated Rochelle's Salt (Na+/K+ Tartrate) (lots
6. customof bubbling so
7. additionadd slowly),
8. stirringthen stirred for an hour
9. filtrationfiltered emulsion (gooey material, very little desired product by LC/MS)
10. washorganics separated, then washed with saturated Rochelle's salt again
11. washwashed with saturated NH4Cl
12. dry with materialorganics dried over sodium sulfate
13. filtrationfiltered
14. concentrationconcentrated
15. customPurification by silica gel chromatography (30-100% EtOAc/Hex; 80 g ISCO)
16. concentrationdesired fractions concentrated