反应详情

In a 1000 mL three neck round bottom flask, a solution of (3aS,6R,6aS)-6-((R)-2, 2-dimethyl-1, 3-dioxolan-4-yl)-2, 2-dimethyldihydrofuro[3,4-d][1,3]dioxol-4(3aH)-one (30 g, 116.2 mmol, 1eq) in THF (600 mL) was treated with TMSCF3 (2M in THF, 122 mL, 244 mmol, commercially available from Sigma Aldrich, India) and tetraethylammonium fluoride (TEAF, 2.48 g, 23.24 mmol, Apollo scientific, UK) at rt under a nitrogen atmosphere. The reaction mixture was stirred at rt for 30 minutes and additional TEAF (24.8 g, 232.4 mmol, Apollo scientific, UK) was added to the reaction mixture. The resulting reaction mixture was stirred at rt for 12 h under a nitrogen atmosphere. Upon completion of the reaction (TLC, 30% EtOAc-hexanes, Rf 0.6), the reaction mixture was diluted with water (1000 mL), and it was then extracted with EtOAc (500 mL×2). The combined organic extracts were washed with water (250 mL), brine (250 mL) and dried over anhydrous Na2SO4. The solution was concentrated under reduced pressure. The residue obtained was purified by silica gel (60-120 mesh) column chromatography (gradient elution, 5-10% EtOAc-hexanes) to give (3aS,6R,6aS)-6-((R)-2,2-dimethyl-1,3-dioxolan-4-yl)-2,2-dimethyl-4-(trifluoromethyl)tetrahydrofuro[3,4-d][1,3]-dioxol-4-ol, as a yellow semi solid mixture of two isomers (27.3 g, 71.8%): 1H NMR (400 MHz, CDCl3) δ 4.95 (m, 2H), 4.78 (d, J=8 Hz, 1H), 4.61-4.32 (m, 2H), 4.23 (dd, J=8, 4 Hz, 1H), 4.18-4.10 (m, 3H), 4.06 (dd, J=8.0, 4.0 Hz, 2H), 3.98 (m, 1H), 1.52 (s, 3H), 1.47 (s, 3H), 1.46 (s, 3H), 1.40 (s, 3H), 1.39 (s, 3H), 1.36 (s, 3H); 19F NMR (376.17 MHz, CDCl3) δ −78.24 & −82.32 ppm.

1. customat rt
2. customThe resulting reaction mixture
3. stirringwas stirred at rt for 12 h under a nitrogen atmosphere
4. extractionwas then extracted with EtOAc (500 mL×2)
5. washThe combined organic extracts were washed with water (250 mL), brine (250 mL)
6. dry with materialdried over anhydrous Na2SO4
7. concentrationThe solution was concentrated under reduced pressure
8. customThe residue obtained
9. customwas purified by silica gel (60-120 mesh) column chromatography (gradient elution, 5-10% EtOAc-hexanes)