Water → (R)-tert-butyl 1-bromopropan-2-ylcarbamate

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Reaction Steps

(R)-tert-Butyl 1-hydroxypropan-2-ylcarbamate (1 g, 5.71 mmol) and carbon tetrabromide (2.84 g, 8.56 mmol) were stirred in CH2Cl2 (20 mL) at −20° C. under argon. A solution of triphenylphosphine (2.40 g, 9.13 mmol) in CH2Cl2 (5 mL) was added dropwise. The reaction was allowed to reach rt and stirred for 14 h. H2O (50 mL) was added to the reaction mixture and the aqueous layer was removed and the CH2Cl2 layer was dried over Na2SO4, filtered, and evaporated. The residue was applied to a silica ISCO column and eluted with 5:1 hexanes/EtOAc. Intermediate 5A (0.68 g, 2.86 mmol, 50.0% yield) was isolated as a white solid. LC-MS (ESI) 183.9 (M−tBu+H), RT=1.76 min (Method B).

Provenance & Evidence