乙基 (1R,2R,4S)-7-氧杂双环[2.2.1]庚烷-2-羧酸乙酯

反应条件: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: (1R,2R,4S)-ethyl 7-oxabicyclo[2.2.1]heptane-2-carboxylate (3.63 g, 21.33 mmol) was dissolved in ethanol (107 ml) and cooled to 0° C. Sodium borohydride (4.84 g, 128 mmol) was added portionwise and the reaction was warmed to room temperature and stirred overnight. The reaction was quenched with saturated NH4Cl solution and extracted three times with ethyl acetate. The combined organic layers were washed with brine, dried over sodium sulfate, filtered, and concentrated. The material was purified via column chromatography (RediSep Gold 40 g, gradient elution 0-100% EtOAc:Heptane) to afford (1R,2S,4S)-7-oxabicyclo[2.2.1]heptan-2-ylmethanol (0.973 g, 7.59 mmol, 35.6% yield) as a clear colorless oil. 1H NMR (400 MHz, CHLOROFORM-d) δ=4.57 (t, J=5.0 Hz, 1H), 4.49 (d, J=5.1 Hz, 1H), 3.78 (dd, J=6.8, 10.7 Hz, 1H), 3.57 (dd, J=9.3, 10.6 Hz, 1H), 3.51-3.42 (m, 2H), 2.44-2.31 (m, 1H), 2.00-1.92 (m, 1H), 1.85-1.79 (m, 1H), 1.76-1.69 (m, 2H), 1.60 (dd, J=8.6, 12.1 Hz, 1H), 1.49-1.43 (m, 2H), 1.39-1.31 (m, 1H), 1.29-1.24 (m, 1H), 0.94 (dd, J=5.1, 11.9 Hz, 1H) the reaction was warmed to room temperature The reaction was quenched with saturated NH4Cl solution extracted three times with ethyl acetate The combined organic layers were washed with brine dried over sodium sulfate filtered concentrated The material was purified via column chromatography (RediSep Gold 40 g, gradient elution 0-100% EtOAc:Heptane)

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: A flask was charged with (1R,2R,4R)-ethyl 7-oxabicyclo[2.2.1]hept-5-ene-2-carboxylate (3.91 g, 23.25 mmol) and ethanol (35 mL). The solution was degassed with nitrogen for 5 minutes, then palladium on carbon (5 wt. % wet) (1.0 g, 0.470 mmol) was added portionwise. The flask was evacuated and backfilled three times with nitrogen, then evacuated and backfilled with hydrogen (balloon). The reaction was stirred overnight at room temperature. The reaction was filtered through a plug of Celite and washed several times with ethanol, making sure to keep the catalyst wet with solvent (a layer of sand was added after the first wash). The filtrate was concentrated to afford (1R,2R,4S)-ethyl 7-oxabicyclo[2.2.1]heptane-2-carboxylate (3.63 g, 21.33 mmol, 92% yield). 1H NMR (400 MHz, CHLOROFORM-d) S=4.82 (d, J=5.0 Hz, 1H), 4.72 (t, J=5.0 Hz, 1H), 4.66 (t, J=5.0 Hz, 1H), 4.63-4.59 (m, 1H), 4.22-4.10 (m, 3H), 3.08-2.97 (m, 1H), 2.59 (dd, J=4.9, 9.1 Hz, 1H), 2.14 (dtd, J=2.6, 5.0, 12.3 Hz, 1H), 1.95-1.87 (m, 1H), 1.83-1.63 (m, 4H), 1.62-1.41 (m, 3H), 1.34-1.21 (m, 4H) The solution was degassed with nitrogen for 5 minutes The flask was evacuated evacuated The reaction was filtered through a plug of Celite washed several times with ethanol was added after the first wash) The filtrate was concentrated