Acetic Acid → 2-Cyclopenten-1-one, 2-ethyl-3-(3-oxo-1-butenyl)-, (E)-

Participants

Reaction Steps

0.968 (0.023 mole) of a 57% NaH dispersion was transferred into a dry 250 ml flask equipped with a magnetic stirring bar and nitrogen inlet. The NaH was covered with 60 ml of dry DME and a solution of 4.15 g (0.025 mole) of dimethyl (2-oxopropyl) phosphonate in 10 ml of DME was added dropwise. The resulting reaction mixture was stirred for one hour at room temperature. Crude aldehyde 5 supra [from oxidation of 3.4 g (0.025 mole) of the vinyl compound 4] in 15 ml of DME was added dropwise, and the stirring was continued for 2 hours after completion of the addition. The reaction mixture was neutralized with acetic acid and 150 ml of water added. The resulting solution was extracted four times each with 100 ml of ether, and the combined ether extracts back-extracted with 100 ml water and once with 75 ml saturated NaCl. The extracts were dried over MgSO4 and concentrated to yield 3.3 g of crude dione Ib. This material was chromatographed on silicic acid using ethyl acetate-cyclohexane to give a bright yellow liquid: uv (95% ethanol) 293 nm; ir (neat) 1685, 1665, 1640 and 1580 cm-1 (conjugated enone system); ##STR5## and 1.0 (t,3,CH2CH3).

Provenance & Evidence