Triphenylphosphine → HCID 85323773, compound

Participants

Reaction Conditions

Reaction Steps

A cold (0° C.) solution of triphenylphosphine (1.143 g., 4.36 mmol.) in tetrahydrofuran (20 ml.) was treated with diisopropyl azidodicarboxylate (860 μl., 883 mg., 4.37 mmol.). Within 5 minutes a white slurry developed. After 30 minutes, a solution of [S-(R*,R*)-2-[(2-phthalimido-4-hydroxy-1-oxobutyl]-amino]-6,6-dimethoxyhexanoic acid, methyl ester [prepared as described in Example 1(f), 928 mg., 2.19 mmol.] in tetrahydrofuran (8 ml.) was added followed by neat thioacetic acid (312 μl., 332 mg., 4.36 mmol.). The mixture was stirred at 0° C. for 1.25 hours, then partitioned between 50% saturated sodium bicarbonate and ethyl acetate. The ethyl acetate extract was washed with brine, dried (sodium sulfate), filtered and stripped. The residue was redissolved in ethyl acetate and treated with a small amount of hexane to precipitate triphenylphosphine oxide. The mixture was filtered and the filtrate was flash chromatographed (Merck silica gel, 65:35-ethyl acetate:hexanes) to give 894 mg. of the title product as a colorless oil. TLC (75:25-ethyl acetate:hexanes) Rf =0.43.

Provenance & Evidence