Ammonium Chloride → 4-Ethynyloxan-4-ol

Participants

Reaction Steps

A stirred solution of dihydro-2H-pyran-4(3H)-one (500 mg, 5.0 mmol) in dry THF (20 mL) was cooled to −70° C. and 0.5 M ethynylmagnesium chloride in THF (20 mL, 10 mmol) was added in a slow stream. The cooling bath was allowed to expire and the mixture was stirred as it warmed to rt. After 6 h, satd aq NH4Cl (20 mL) was added and the mixture was concentrated on the rotary evaporator. The aqueous residue was extracted with EtOAc (2×50 mL). The combined organic extracts were washed with brine, dried over Na2SO4 and concentrated to leave crude 4-ethynyltetrahydro-2H-pyran-4-ol (491 mg, 78%) as a brown oil. 1H NMR (CDCl3) 1.80 (m, 2H), 1.92 (m, 2H), 2.57 (s, 1H), 3.68 (m, 2H), 3.90 (m, 2H).

Provenance & Evidence