[O:1]1[CH2:5]CC[CH2:2]1.C([N-]C(C)C)(C)C.[Li+].C1(P(=O)(C2C=CC=CC=2)COC)C=CC=CC=1.[CH3:31][C:32]([CH3:38])([CH2:35][CH:36]=[CH2:37])[CH:33]=O>O>[CH3:2][O:1][CH:5]=[CH:33][C:32]([CH3:31])([CH3:38])[CH2:35][CH:36]=[CH2:37]
To a freshly prepared tetrahydrofuran (300 mL) solution of lithium diisopropylamide (0.19 mol) under nitrogen at 0° C. was added dropwise in 30 minutes a tetrahydrofuran (200 mL) solution of diphenyl(methoxymethyl)phosphinoxide (49.5 g, 0.2 mol). After stirring for 15 minutes at 0° C., a tetrahydrofuran (100 mL) solution of 2,2-dimethylpent-4-enal (24.5 g, 0.22 mol) was added dropwise in 20 minutes to the cherry-colored mixture. After 15 minutes, the mixture was warmed to room temperature and then refluxed for 5 hours. The mixture was cooled to room temperature, charged with water (20 mL), and cooled at 0° C. under vigorous stirring. The resulting solid was filtered, washed with hexanes, and discarded. The filtrates were collected and distilled at 101-102° C. (155 mmHg) to give the title compound as a colorless oil.
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