tert-butyl 2,5-dihydrofuran-3-carboxylate

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)