Triethylamine → (S)-2-tert-Butoxycarbonylamino-5-(tert-butyl-diphenyl-silanyloxy)-pentanoic acid benzyl ester

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Reaction Steps

(S)-2-tert-Butoxycarbonylamino-5-hydroxy-pentanoic acid benzyl ester (2.5 g) was dissolved in 50 ml DMF and treated with 2.0 ml tert-butyldiphenylchlorosilane, 1.2 ml triethylamine and 95 mg DMAP. After stirring for 12 h equivalent portions of the reagents were added and the mixture stirred for additional 12 h. The mixture was concentrated, the residue was dissolved in ethyl acetate and washed with aqueous LiCl (4%), 0.1 M HCl and saturated aqueous NaHCO3. The crude product obtained after evaporation of the solvent was purified by flash chromatography on silica using an ethyl acetate/heptane gradient. Yield: 2.0 g.

Provenance & Evidence