[F:1][C:2]([F:10])([F:9])[C:3]([CH3:8])([CH3:7])[C:4](O)=[O:5].C(Cl)(=O)C(Cl)=O.[CH3:17][O:18]/[CH:19]=[CH:20]/[C:21](=[O:23])[CH3:22].[Li+].C[Si]([N-][Si](C)(C)C)(C)C.N#N.FC(F)(F)C(C)(C)C(Cl)=O>C(Cl)(Cl)Cl.C1COCC1>[F:1][C:2]([F:10])([F:9])[C:3]([CH3:8])([CH3:7])/[C:4](/[OH:5])=[CH:22]/[C:21](=[O:23])/[CH:20]=[CH:19]/[O:18][CH3:17]
To a mixture of 3,3,3-trifluoro-2,2-dimethylpropanoic acid (10 g, 64.1 mmol) in CHCl3 (100 mL) cooled to 0° C. was added oxalyl chloride (7.29 mL, 83 mmol) dropwise. The mixture was stirred at 70° C. for 4 h. Then the mixture was concentrated. To a mixture of (E)-4-methoxybut-3-en-2-one (12.83 g, 128 mmol) in THF (100 mL) cooled to −78° C. was added LiHMDS (128 mL, 128 mmol) dropwise under N2. The mixture was stirred at −78° C. for 1 h. Then to the mixture was added a solution of 3,3,3-trifluoro-2,2-dimethylpropanoyl chloride in THF (100 mL) at −78° C. The whole mixture was allowed to warm to rt over 2 h and quenched by NH4Cl (saturated aqueous, 30 mL). THF was removed under vacuum. To the mixture was added H2O (80 mL) and then extracted with EA (100 mL×3). The organic layer was washed with brine (80 mL), dried over Na2SO4, filtered and concentrated. The crude material was purified by silica column chromatography (PE/EA=2:1). All fractions found to contain product by TLC (PE/EA=2:1, Rf=0.5) were combined to yield an off-white oil of (1E,4Z)-7,7,7-trifluoro-5-hydroxy-1-methoxy-6,6-dimethylhepta-1,4-dien-3-one (1 g, 3.36 mmol, 5.2% yield): 1H NMR (400 MHz, CDCl3): δ 15.90 (s, 1H), 7.65 (d, J=12.4 Hz, 1H), 5.63 (s, 1H), 5.33 (d, J=12.4 Hz, 1H), 3.74 (s, 3H), 1.38 (s, 6H). ES-LCMS m/z 239.1 (M+H).
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