Dimethyl (2-oxopropyl)phosphonate → methyl(3E)-2,2-dimethyl-5-oxohex-3-enoate

Participants

Reaction Steps

To a solution of dimethyl (2-oxopropyl)phosphonate (4.09 mL, 30.0 mmol) in tetrahydrofuran (200 mL) at 0° C. was added potassium tert-butoxide (3.22 g, 28.7 mmol). After 15 minutes the reaction mixture was moved to room temperature, and after an additional 15 minutes methyl 2,2-dimethyl-3-oxopropanoate (3.39 g, 26.0 mmol) was added. The opaque reaction mixture was stirred for 21 hours and then partitioned between diethyl ether (100 ml) and water (100 mL). The layers were separated and the aqueous layer was extracted with diethyl ether (100 mL, 50 mL). The combined organic layers were washed with aqueous saturated sodium bicarbonate solution and brine, dried over sodium sulfate, filtered, and concentrated under reduced pressure. The residue was purified by chromatography on silica gel (0-4% methanol/dichloromethane) to yield methyl (3E)-2,2-dimethyl-5-oxohex-3-enoate. 1H NMR (500 MHz, CDCl3) δ 6.95 (d, J=16.4 Hz, 1H), 6.09 (d, J=16.4 Hz, 1H), 3.71 (s, 3H), 2.29 (s, 3H), 1.37 (s, 6H).

Provenance & Evidence