反应详情

Lithium bis(trimethylsilyl)amide (1.06 M in THF; 20.6 mL, 21.9 mmol) was added dropwise over 10 min to a stirred solution of benzyl (4-bromophenyl)acetate (6.07 g, 19.9 mmol) in THF (60 mL) at −78° C. under nitrogen. On completion of addition stirring was continued at −78° C. for 30 min then t-butylbromoacteate (4.65 g, 3.52 mL, 23.9 mmol) was added dropwise over 5 min. The reaction was allowed to warm slowly to room temperature over 4 h then saturated ammonium chloride solution (50 mL) was added and the resulting suspension extracted with ethyl acetate (3×100 mL). The organic phases were combined, dried (magnesium sulfate) and evaporated to dryness. The residue was chromatographed on silica gel (10% diethyl ether: cyclohexane) to give the title compound as a colourless oil (6.82 g, 82%). LC/MS: 3.90 min; z/e 419 and 421, calcd (M+1) 419 and 421. 1H NMR (400 MHz: CDCl3): 7.40 (2H), 7.30 (5H), 7.15 (2H), 5.10 (2H), 4.05 (1H), 3.05 (1H), 1.35 (9H).

1. additionOn completion of addition
2. extractionthe resulting suspension extracted with ethyl acetate (3×100 mL)
3. dry with materialdried (magnesium sulfate)
4. customevaporated to dryness
5. customThe residue was chromatographed on silica gel (10% diethyl ether: cyclohexane)