Acetone → HCID 13489928, compound

Participants

Reaction Steps

A 3.42-g (84.2-mmol) portion of 59% NaH-mineral dispersion was washed with pentane (20 mL, 2×10 mL). To the NaH remaining was added with stirring 85 mL of DMF followed by 27.8 g (84.2 mmol) of diethyl 4-carbethoxy-2-methoxybenzylphosphonate in 10 mL of DMF (5-mL DMF rinse). The reaction mixture turned deep yellow. After 3.5 h of stirring, when hydrogen evolution ceased, 32.0 mL (436 mmol) of acetone was added with cooling in a cold water bath to maintain the internal temperature at 20°-30° C. The orange reaction mixture was then stirred at room temperature for 13 h before dilution with 600 mL of Et2O and 400 mL of H2O containing 4 mL of HOAc. The aqueous layer was extracted with 400 mL of Et2O. The combined Et2O extracts were washed with water (3×100 mL) and brine (2×100 mL), dried (MgSO4), and concentrated to 19.8 g of a yellow oil. This material was chromatographed on 500 g of silica gel with 10% Et2O/hexane to afford in fractions 15 to 23 (125-mL volume) 14.4 g (73% yield) of a colorless oil (TLC Rf 0.27), which solidified to off-white prisms, mp 42° C.; IR (film) 1720, 1470, 1420, 1300, 1280, 1260, 1110, 1040 cm-1 ; 1H NMR (CDCl3) δ 1.40 (t, J=7 Hz, 3, CO2CH2CH3), 1.82 (d, J=0.5 Hz, 3, C=CCH3), 1.98 (d, J=0.5 Hz, 3, C=CCH3), 3.90 (s, 3, OCH3), 4.42 (q, J=7 Hz, 2, CO2CH2CH3), 6.38 (broad s, 1, C=CH), 7.26 (d, J=8 Hz, 1, 5' H), 7.60 (d, J=2 Hz, 1, 2' H), 7.70 (dd, J=8 Hz, J=2 Hz, 1, 6' H); MS calcd for C14H18O3 234.1256, found 234.1259. Further elution of the column afforded a viscous yellow oil (Rf 0.19).

Provenance & Evidence