Lithium Hexamethyldisilazide → 1-(3-Bromo-4-fluorophenyl)-2-[4-(2-fluoroethoxy)-phenyl]ethane-1,2-dione

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Reaction Conditions

Reaction Steps

A 1.0 M solution of lithium bis(trimethylsilyl)amide in tetrahydrofuran (20 mL, 20 mmol was added at room temperature to a stirred suspension of (3-bromo-4-fluoro-benzyl)triphenylphosphonium bromide (10.6 g, 20 mmol) in tetrahydrofuran (40 mL). The mixture was stirred for 40 minutes, then cooled to −20° C. and treated with 4-(2-fluoroethoxy)benzoyl chloride (4.1 g, 20 mmol) in tetrahydrofuran (40 mL) and stirred for an additional 2 hours while slowly warming to room temperature. The mixture was treated with water (20 mL) and sodium periodate (4.3 g, 20 mmol) then stirred at 50° C. for 18 hours. After cooling to room temperature the mixture was extracted with ethyl acetate. The organic extracts were washed with brine, dried over MgSO4. Evaporation and purification by flash chromatography (hexane/ethyl acetate 9/1) gave a yellow solid (3 g, 41% yield); 1H NMR (400 MHZ, CDCl3) δ 4.25 (m, 1H), 4.32 (m, 1H,) 4.70 (m, 1H), 4.82 (m, 1H), 7.01 (d, 2H), 7.23 (m, 1H), 7.94 (m, 3H), 8.22 (m, 1H); MS m/e (M+CH3COO)− 427; mp 107° C.

Provenance & Evidence