Phosphorus trichloride → TRANS 5-(t-BUTYLDIPHENYLSILYLOXYMETHYL)-2-(DIETHYLOXYPHOSPHINOYL)-1,3-OXATHIOLANE

Participants

Reaction Steps

A solution of triethylorthoformate (0.64 g, 4.33 mmol), 1-t-butyldiphenylsilyloxy-3-mercapto-2-propanol (example 24) (5.00 g, 46.23 mmol) and p-toluenesulfonic acid (20 mg) in toluene (60 mL) was heated to reflux for 2 h. The solvent was removed under reduced pressure to give a yellow oil. The oil was dissolved in dichloromethane (20 mL), zinc chloride (20 mg) was added along with triethyl phosphite (0.32 g, 1.93 mmol) at 0° C., followed by the addition of phosphorous trichloride (0.13 g, 0.95 mmol). After stirring at room temperature for 18 h the solvent was removed under reduced pressure to give a colorless oil. The crude material was purified by flash chromatography with a mixture of hexanes and ethyl acetate (50:50) to give the compound as a colorless oil (0.97 g) in 67% yield as a mixture of cis and trans isomers (1:3.5).

Provenance & Evidence