(Diethylamino)sulfur trifluoride → Benzyl 4-fluoro-4-methyltetrahydrofuran-3-ylcarbamate

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Reaction Steps

(Diethylamino)sulphur trifluoride (2.103 mL, 15.92 mmol) was added dropwise to a solution of impure benzyl 4-hydroxy-4-methyltetrahydrofuran-3-ylcarbamate (2.00 g, from Step 4) in dichloromethane (50 mL) at −78° C. After 45 min at −78° C., the mixture was quenched with saturated sodium bicarbonate (100 mL) and allowed to warm to room temperature. After separation of the two phases, the aqueous phase was extracted with dichloromethane (3×50 mL). The combined extracts were dried (MgSO4) and concentrated. The mixture was purified by silica gel chromatography, eluting with 10-50% ethyl acetate in hexanes. None of the fractions were found to be free of impurities. All fractions containing the desired product were combined to give impure benzyl 4-fluoro-4-methyltetrahydrofuran-3-ylcarbamate (597 mg). The mixture was taken to the next step without purification.

Provenance & Evidence