C[Si]([C:5]#[C:6][C:7]1[C:12]([CH3:14])([CH3:13])[CH2:11][C:10]([CH3:16])([CH3:15])[CH2:9][C:8]=1[C:17]1[CH:22]=[CH:21][C:20]([F:23])=[C:19]([CH3:24])[CH:18]=1)(C)C.C(O)(=O)C.[F-].C([N+](CCCC)(CCCC)CCCC)CCC>C1COCC1.CCOCC>[C:6]([C:7]1[C:12]([CH3:14])([CH3:13])[CH2:11][C:10]([CH3:16])([CH3:15])[CH2:9][C:8]=1[C:17]1[CH:22]=[CH:21][C:20]([F:23])=[C:19]([CH3:24])[CH:18]=1)#[CH:5]
To a solution of the product from Example 1, Step D above (5 g, 14.6 mmol), and acetic acid (1.3 ml, 21.9 mmol) in THF (15 ml) at 0° C. is added tetrabutylammonium fluoride in THF (1M, 21.9 ml, 21.9 mmol). The resulting solution is stirred for 12 hours at room temperature, diluted with ether and washed with saturated ammonium chloride solution. The ether fraction is dried over MgSO4, and the solvent is removed under reduced pressure. Purification by silica gel chromatography (100% hexane) provides 3.9 g (98%) of 1-(ethynyl)-2-(4-fluoro-3-methylphenyl)-4,4,6,6-tetramethyl-1-cyclohexene: 1H NMR δ=1.0 (s,6), 1.22 (s,6), 1.45 (s,2), 2.15 (s,2), 2.25 (s,3), 2.75 (s,1), 6.95 (t,1), 7.15 (m,2).
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