反应详情

A solution of carbon tetrabromide (2.82 g, 8.5 mmol) in dichloromethane (3 ml) was added dropwise over 10 min to a stirred solution of (R)-[4-chlorophenyl][(2R)-4-benzylmorpholin-2-yl]methanol and (S)-[4-chlorophenyl][(2S)-4-benzylmorpholin-2-yl]methanol (1.80 g, 5.67 mmol) and triphenylphosphine (2.23 g, 8.5 mmol) in dichloromethane (40 ml) at room temperature under nitrogen. After 30 min, the reaction solution was washed with saturated aqueous sodium bicarbonate (50 ml). The dichloromethane layer was dried, filtered and evaporated to a red liquid (8.5 g). Trituration with diethyl ether (20 ml) crystallised triphenylphoshine oxide that was then removed by filtration. The filtrate was evaporated to a yellow oil and was purified by chromatography on silica eluting with ethyl acetate:hexane 20:80 to give a colourless oil of (2R)-2-[(S)-bromo(4-chlorophenyl)methyl]-4-benzylmorpholine and (2S)-2-[(R)-bromo(4-chlorophenyl)methyl]-4-benzylmorpholine (1.17 g) that crystallised to a pink solid on standing.

1. washthe reaction solution was washed with saturated aqueous sodium bicarbonate (50 ml)
2. dry with materialThe dichloromethane layer was dried
3. filtrationfiltered
4. customevaporated to a red liquid (8.5 g)
5. customTrituration with diethyl ether (20 ml) crystallised triphenylphoshine oxide that
6. customwas then removed by filtration
7. customThe filtrate was evaporated to a yellow oil
8. customwas purified by chromatography on silica eluting with ethyl acetate:hexane 20:80