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温度

0 °C

Trifluoromethanesulfonic anhydride (11.1 mL, 66.2 mmol), followed by triethylamine (17.8 mL, 127.4 mmol) was added to a slurry of 4-(hydroxymethyl)tetrahydropyran-4-carboxylic acid (10.20 g, 63.68 mmol) in anhydrous diethyl ether cooled to 0° C. (115 mL). The biphasic solution was stirred for 20 hours, warmed to room temperature, stirred an additional 2 hours. The layers were separated by decantation, and the lower layer diluted with 2% aqueous sodium bicarbonate solution (50 mL) and extracted with methylene chloride (4×200 mL). The combined organic extracts were washed with additional 2% aqueous sodium bicarbonate (100 mL), dried over magnesium sulfate, and concentrated in vacuo to afford 2,7-dioxaspiro[3.5]nonane-1-one as a pale yellow oil (10.8 g). IR (KBr) 1821 cm-1 ; 1HNMR (CD3Cl3) δ 1.92 (ddd, J=13.4, 8.1, 4.0 Hz, 2H) , 2.10 (dddd, J=13.4, 6.1,3.4, 0.8 Hz, 2H), 3.70 (ddd, J=11.8, 6.3, 3.9 Hz, 2H), 3.92 (ddd, J=11.8, 7.9, 3.4 Hz, 2H), 4.15 (s, 2H); 13CNMR (CD3Cl3) δ 30.78 (t), 55.78 (s), 64,46 (t), 71.50 (t), 173.42 (s), MS(EI) m/e=142. MS(CI) M+=H m/e=143, M++HNH4 m/e=160.

1. temperaturewarmed to room temperature
2. stirringstirred an additional 2 hours
3. customThe layers were separated by decantation
4. additionthe lower layer diluted with 2% aqueous sodium bicarbonate solution (50 mL)
5. extractionextracted with methylene chloride (4×200 mL)
6. washThe combined organic extracts were washed with additional 2% aqueous sodium bicarbonate (100 mL)
7. dry with materialdried over magnesium sulfate
8. concentrationconcentrated in vacuo