Imidazole → (1S)-[1-(tert-Butyldimethylsilanyloxymethyl)-3-(tritylcarbamoyl)propyl]carbamic Acid Benzyl Ester

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Reaction Steps

Intermediate B1, prepared above, was dissolved in DMF (10 mL). Imidazole (2.69 g, 39.5 mmol, 2.3 equiv) and tert-butyldimethylsilyl chloride (2.86 g, 19.0 mmol, 1.1 equiv) were added. The reaction mixture was stirred overnight, then diluted with MTBE (500 mL) and washed sequentially with 2.5% KHSO4, H2O, NaHCO3, H2O, and brine (100 mL each). The organic phase was dried over MgSO4 and evaporated. The residue was purified by flash column chromatography (gradient elution, 25→40% EtOAc in hexanes) to provide the title intermediate (7.6 g, 71%) as a white amorphous solid: IR (cm−1) 3307, 1708, 1660, 1496, 1249; 1H NMR (CDCl3) δ-0.01-0.05 (m, 6H), 0.89 (s, 9H), 1.76-1.93 (m. 2H), 2.29-2.40 (m, 2H), 3.56-3.77 (m, 3H), 5.03-5.16 (m, 3H), 7.00 (s, 1H), 7.18-7.39 (m, 20 H); Anal. C38H46N2O4Si: C, H, N.

Provenance & Evidence