C[Si](C)(C)[N-][Si](C)(C)C.[Li+].[F:11][C:12]1[CH:17]=[CH:16][CH:15]=[CH:14][C:13]=1[CH2:18][C:19]([O:21][CH3:22])=[O:20].[F:23][C:24]1[C:25]([C:31](Cl)=[O:32])=[N:26][CH:27]=[C:28]([F:30])[CH:29]=1.[Cl-].[NH4+]>C1COCC1.O>[F:23][C:24]1[C:25]([C:31](=[O:32])[CH:18]([C:13]2[CH:14]=[CH:15][CH:16]=[CH:17][C:12]=2[F:11])[C:19]([O:21][CH3:22])=[O:20])=[N:26][CH:27]=[C:28]([F:30])[CH:29]=121.4 ml (21.4 mmol) of lithium hexamethyldisilazide (1.0 M in THF) were initially charged in THF (30 ml) under argon and a solution of 3.00 g (17.8 mmol) of methyl 2-fluorophenylacetate in THF (15 ml) was added dropwise at −78° C. The reaction mixture was stirred at −78° C. for 1 h, and then a solution of 3.80 g (21.4 mmol) of the compound from Example 12A in THF (15 ml) was added dropwise. The solution was stirred at −78° C. for 1 h, then brought to RT, and saturated aqueous ammonium chloride solution was added in portions. The mixture was diluted with water and extracted twice with ethyl acetate. The combined organic phases were dried over sodium sulphate, filtered and concentrated. The residue was stirred with MTBE, the solids were filtered off and the filtrate was concentrated. Silica gel chromatography (eluent: 30:1, 20:1 cyclohexane-ethyl acetate) of the residue gave 3.66 g (87% purity, 57% of theory) of the title compound. The crude product was converted without further purification.
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