反应详情

A suspension of 3.29 g (0.01 mole) of 1-diethoxyphosphinyl-2-(3-pyridinyl)ethanesulfonic acid lithium salt (from part I of Example 16) in 50 ml of anhydrous tetrahydrofuran is stirred in a -40° bath under a dry nitrogen atmosphere. To this is added n-butyl lithium (4.4 ml of 2.5M solution in hexanes; 0.011 mole) via syringe over 5 minutes. The reaction mixture is allowed to warm to -15° , and is stirred at this temperature for about one hour. It is then cooled to -78°, and to it is added dropwise a solution of 3.44 g (0.015 mole) of camphorylsulfonyloxaziridine (J. Am. Chem. Soc., 112, 6679(1990)) in 50 ml of anhydrous THF. The reaction mixture is stirred for a few minutes at -78°, and then is placed in an ice/water bath. It is stirred at 0° for 2-10 minutes, and then is again cooled to -78° . The reaction mixture is quenched by addition of 1.2 g (0.02 mole) of acetic acid and the solvents are removed under vacuum on a rotary evaporator. The residue was purified by chromatography on silica gel using chloroform/methanol as eluant, to yield 1-diethoxyphosphinyl-1-hydroxy-2-(3-pyridinyl)ethanesulfonic acid lithium salt.

1. temperatureto warm to -15°
2. stirringis stirred at this temperature for about one hour
3. temperatureIt is then cooled to -78°
4. stirringThe reaction mixture is stirred for a few minutes at -78°
5. customis placed in an ice/water bath
6. stirringIt is stirred at 0° for 2-10 minutes
7. temperatureis again cooled to -78°
8. customthe solvents are removed under vacuum on a rotary evaporator
9. customThe residue was purified by chromatography on silica gel