[CH3:1][C:2]([CH2:9][CH2:10][CH:11]=[C:12]([CH3:14])[CH3:13])=[CH:3][CH:4]=[CH:5][C:6](=[O:8])[CH3:7].CC(C)=CCC/C(/C)=C/C=C/C(C)=O.CC(=CCCC(=CC=O)C)C.CC(C)=O>[Pd].C(O)C>[CH3:1][CH:2]([CH2:9][CH2:10][CH2:11][CH:12]([CH3:14])[CH3:13])[CH2:3][CH2:4][CH2:5][C:6](=[O:8])[CH3:7]
A mixture of 17.82 g (92.8 mmoles) of 6,10-dimethyl-3,5,9-undecatrien-2-one ("pseudoionone", prepared from citral and acetone as described by A. Russell, et al., Organic Syntheses, Collective Volume-3, pages 747-750) and 1.0 g of 5% palladium on activated carbon in 50 mL of absolute ethyl alcohol was shaken vigorously under a hydrogen atmosphere (approximately 2-3 atm. pressure) for 30 minutes. After removal of the catalyst by filtration through a small pad of Hyflo Super-Cel® filtering aid, the filtrate was diluted with 150 mL of hexane. The organic layer was subsequently washed with water (2×400 mL), then dried over anhydrous magnesium sulfate, and re-filtered. Removal of the hexane by evaporation at reduced pressure, followed by distillation, afforded 15.95 g (87% yield) of 6,10-dimethyl-2-undecanone: boiling point 68°-72° C. at 0.15 mm. A previous synthesis of the latter ketone has been reported by F. G. Fischer, et al., Ann., 475, 183 (1929).
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