Water → tert-butyl (2S,3S)-3,4-bis(tert-butyldimethylsilyloxy)-1-hydroxybutan-2-ylcarbamate

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Reaction Steps

A solution of tert-butyl (1R,2S)-2,3-bis(tert-butyldimethylsilyloxy)-1-(thiazol-2-yl)propylcarbamate (6.150 g, 12.2 mmol) in 120 mL MeCN was treated with 4A mol. sieves and was allowed to stir at room temperature for 10 minutes. Methyl trifluoromethylsulfonate (1.62 ml, 14.7 mmol) was added, and the reaction mixture was allowed to stir for an additional 30 minutes. The reaction mixture was then concentrated in vacuo. The crude residue was dissolved in 100 mL MeOH, cooled to 0° C., and treated with NaBH4 (1.39 g, 36.7 mmol). The reaction mixture was allowed to warm to RT and stir for an additional 20 minutes. The reaction mixture was then concentrated, diluted with EtOAc, filtered through celite and again concentrated in vacuo. The residue was dissolved in 100 mL ACN and 20 mL water and was treated with mercury(II)chloride (3.32 g, 12.2 mmol). After stirring for 30 minutes, an additional portion of NaBH4 (1.39 g, 36.7 mmol) was added, and the reaction mixture was allowed to stir for another 30 minutes. The reaction mixture was quenched with saturated NaHCO3 solution and diluted with EtOAc. The crude reaction mixture was then washed with water then brine. The organic layer was dried over MgSO4 and concentrated in vacuo. The crude residue was forced through a short plug of silica eluting with ether. The filtrate was again concentrated in vacuo yielding tert-butyl (2S,3S)-3,4-bis(tert-butyldimethylsilyloxy)-1-hydroxybutan-2-ylcarbamate (5.33 g, 96.9% yield) with minor impurities.

Provenance & Evidence