Reaktion #2793

Reaktionsgleichung

acetic acid

n-butyl lithium

1-diethoxyphosphinyl-2-(3-pyridinyl)ethanesulfonic acid lithium salt

→

1-diethoxyphosphinyl-1-hydroxy-2-(3-pyridinyl)ethanesulfonic acid lithium salt

Lösungsmittel

tetrahydrofuran

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturto warm to -15°
2. 2
   workup.STIRRINGis stirred at this temperature for about one hour
3. 3
   TemperaturIt is then cooled to -78°
4. 4
   workup.STIRRINGThe reaction mixture is stirred for a few minutes at -78°
5. 5
   Sonstigeis placed in an ice/water bath
6. 6
   workup.STIRRINGIt is stirred at 0° for 2-10 minutes
7. 7
   Temperaturis again cooled to -78°
8. 8
   Sonstigethe solvents are removed under vacuum on a rotary evaporator
9. 9
   SonstigeThe residue was purified by chromatography on silica gel

Vorschrift

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.

Quelle