trans-3-hydroxy-L-proline → 1,1-Dimethylethyl (2R,3S)-3-[[(1,1-dimethylethyl)dimethylsilyl]oxy]-2-(hydroxymethyl)-1-pyrrolidinecarboxylate

Participants

Reaction Steps

Following procedures described for the preparation of (2S,3R)—N-tert-butyloxycarbonyl-3-(tert-butyldimethylsilanyloxy)proline methyl ester (51A), (2S,3S)-3-hydroxyproline was converted to (2S,3S)—N-tert-butyloxycarbonyl-3-(tert-butyldimethylsilanyloxy)proline methyl ester. To this material (4.3 g, 12 mmol) in THF (75 mL) at −78° C. under nitrogen was added dropwise 1.0 M lithium triethylborohydride in THF (60 mL, 60 mmol). The reaction was allowed to warm to rt and was stirred for 4 h. The reaction was quenched by pouring over ice (150 g) and stirring for 30 min. The product was extracted into EtOAc and washed with saturated aqueous NaHCO3. The organics were dried over MgSO4, filtered and concentrated. Purification by flash chromatography (silica gel, 0-15% EtOAc in hexanes) provided the title compound (3.3 g).

Provenance & Evidence