[H-].[Na+].[C:3]([O:12]C)(=O)[CH2:4][CH2:5][CH2:6][C:7]([CH3:10])([CH3:9])[CH3:8].[C:14]([C:17]1[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=1)(=[O:16])[CH3:15]>C1(C)C(C)=CC=CC=1>[C:17]1([C:14](=[O:16])[CH2:15][C:3]([CH2:4][CH2:5][CH2:6][C:7]([CH3:8])([CH3:9])[CH3:10])=[O:12])[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=1A 500 mL 4 neck round bottom flask equipped with mechanical stirring, a nitrogen inlet, a thermometer, a condenser, and an addition funnel was charged with 60% sodium hydride in mineral oil (20.5 g, 0.51 mol), methyl neo-octanoate (92.3 g, 0.58 mol), and xylene (42.8 g). The mixture was heated to reflux (135° C.), and then a solution of acetophenone (32.4 g, 0.27 mol) in xylene (19.1 g) was added over 1.25 h. The mixture was kept at reflux for an additional 1 h. After cooling to room temperature, the reaction was quenched by the careful addition of methanol (20 mL), and then acidified with 150 g/L sulfuric acid (180 mL). After separation of layers, the organic phase was washed with water (2×100 mL) and brine (100 mL). After drying by passing through anhydrous sodium sulfate, the solution was concentrated in vacuo at 70° C. down to 12 mbar to yield an orange liquid containing product in a crude yield of 63%. Vacuum distillation (200 mtorr) through a 15 cm Vigreux column yielded the product in the heart cut: 1-phenyl-3-neoheptyl-1,3-propanedione (37.2 g, 96% pure, 0.14 mol; 53% yield; bp: 94-135° C.). Dypnone was undetectable in the product.
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