tert-butyl 4-hydroxyoxolane-3-carboxylate

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:2.51; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: The product of Step B, t-butyl 4-hydroxytetrahydrofuran-3-carboxylate (0.83 g, 4.41 mmol) and PPh3 (1.74 g, 6.63 mmol) were placed in THF (5 mL), the solution was cooled to 0-5° C., and DIAD (1.13 mL, 5.74 mmol) was added dropwise. After reacting at rt for 12 h, the reaction mixture was filtered, washed with a solution of EtOAc/Hex=1/4, and the filtrate concentrated in vacuo The residue was purified by column chromatography (eluent, EtOAc/Hex=1/7) to give the title compound (0.39 g, 51.34%). the reaction mixture was filtered washed with a solution of EtOAc/Hex=1/4 the filtrate concentrated in vacuo The residue was purified by column chromatography (eluent, EtOAc/Hex=1/7)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: The product of Step A, tert-butyl 4-oxotetrahydrofuran-3-carboxylate (0.95 g, 5.10 mmol) was placed in isopropylalcohol (14 mL) at 0-5° C., NaBH4 (77 mg, 2.04 mmol) was added, and stirred for 2 h. NaBH (77 mg, 2.04 mmol) was added again, and stirred at rt for 1 h, NaBH4 (39 mg, 1.02 mmol) was added, and stirred for 30 min. The reaction mixture was treated with Et2O to dilute, washed with brine, and extracted with Et2O twice. The organic layer was collected, extracted with a NaHCO3 aqueous solution, dried over MgSO4, filtered, and concentrated in vacuo. The residue was purified by column chromatography (eluent, EtOAc/Hex=1/3) to give the title compound (0.83 g, 86.56%). stirred at rt for 1 h stirred for 30 min to dilute washed with brine extracted with Et2O twice The organic layer was collected extracted with a NaHCO3 aqueous solution dried over MgSO4 filtered concentrated in vacuo The residue was purified by column chromatography (eluent, EtOAc/Hex=1/3)