反应详情

温度

-78 °C

To a solution of toluene (500 mL) at −78° C. was added butyl lithium (1.6 M in hexanes, 75.6 ml, 121 mmol) at a rate such that the internal temperature did not exceed −50° C. To this solution was added 2-bromo-5-fluoropyridine (23.2 g, 132 mmol) in toluene (200 mL) at a rate such that the internal temperature did not exceed −68° C. The reaction was stirred at −78° C. for 1 hour. To the reaction was added (S,E)-N-(2-(tert-butyldimethylsilyloxy)ethylidene)-2-methylpropane-2-sulfinamide (30.5 g, 110 mmol) in toluene (200 mL) at a rate such that the internal temperature did exceed −68° C. The reaction was again stirred at −78° C. for 1 hour. To the reaction was added 200 mL of water and the layers separated. The toluene solution was washed with water (200 mL), brine (200 mL), dried over MgSO4 and concentrated in vacuo. The crude material was chromatographed using 4:1 hexanes/ethyl acetate as eluent to yield (S)—N—((S)-2-(tert-butyldimethylsilyloxy)-1-(5-fluoropyridin-2-yl)ethyl)-2-methylpropane-2-sulfinamide (20 g, 48%).

1. customdid not exceed −50° C
2. customdid not exceed −68° C
3. customdid exceed −68° C
4. stirringThe reaction was again stirred at −78° C. for 1 hour
5. customthe layers separated
6. washThe toluene solution was washed with water (200 mL), brine (200 mL)
7. dry with materialdried over MgSO4
8. concentrationconcentrated in vacuo
9. customThe crude material was chromatographed