Diethyl Ether → 4-(4-Fluorophenoxy)-1-butyn-3-one

Participants

Reaction Steps

A solution of ethynylmagnesium bromide (0.5 M in THF, 508 mL, 254 mmol), was added slowly, as a stream down the side of the flask, to an ice water cooled solution of N-methoxy-N-methyl-2-(4-fluorophenoxy)ethanamide (20.00 g, 74 mmol) in THF (100 mL). After an additional 30 minutes at 0° C., the reaction mixture was poured into a vigorously stirred mixture of 1 M NaH2SO4 (1700 mL) and ether (1 L). The layers were separated and the aqueous layer then extracted with ether (700 mL). The combined organic phases were washed with brine and dried over MgSO4, filtered, and concentrated under vacuum. The residue was purified by eluting through a plug of silica gel (10 cm×3 cm) with 1:4 ether:pet. ether to afford 27.65 g (91% yield) of 4-(4-fluorophenoxy)-1-butyn-3-one, a compound of formula (AA), as a low melting solid; 1H NMR (CDCl3) δ 3.40 (s, 1H), 4.70 (s, 2H), 6.85 (m, 2H), 7.0 (t, 2H) ppm.

Provenance & Evidence