[Si]([O:8][C:9]1[CH:14]=[CH:13][C:12]([Cl:15])=[CH:11][C:10]=1[CH:16]1[CH2:19][N:18]([C:20]([O:22][C:23]([CH3:26])([CH3:25])[CH3:24])=[O:21])[CH2:17]1)(C(C)(C)C)(C)C.[F-].C[N+](C)(C)C>O1CCCC1>[Cl:15][C:12]1[CH:13]=[CH:14][C:9]([OH:8])=[C:10]([CH:16]2[CH2:17][N:18]([C:20]([O:22][C:23]([CH3:25])([CH3:24])[CH3:26])=[O:21])[CH2:19]2)[CH:11]=1To a solution of tert-Butyl 3-(2-{[tert-butyl(dimethyl)silyl]oxy}-5-chlorophenyl)azetidine-1-carboxylate (Preparation 238, 3.1 g, 7.79 mmol) in tetrahydrofuran (80 ml) was added tetramethylammonium fluoride (1.0 g, 10.74 mmol). The mixture was stirred at room temperature for 18 hours before concentrating in vacuo. The residue was partitioned between tert-butyl methyl ether (100 ml) and aqueous sodium hydroxide solution. The organics were dried over sodium sulfate, filtered and evaporated in vacuo to give a reddish brown oil, 2.33 g. This was purified by column chromatography (100 g of silica) eluting with heptane:ethyl acetate (6:4, by volume) to afford the title compound as a reddish brown gum, 850 mg, 38% yield.
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