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

Participants

Reaction Steps

A solution of (R)-tert-butyl 1-hydroxypropan-2-ylcarbamate (100 mg, 571 μmol) and carbon tetrabromide (303 mg, 913 μmol) was cooled on an ice bath. Triphenylphosphine (299 mg, 1141 μmol) was added and the reaction was stirred for 10 min. The reaction was then allowed to warm to r.t. and stirred for 18 hours. After this time, a TLC suggested that the reaction was complete (silica, 50% EtOAc/Hexanes, Ninhydrin stain). The solvent was removed and the product purified by column chromatography (0, 5, 10, 15, 20% EtOAc/Hexanes) to yield (R)-tert-butyl 1-bromopropan-2-ylcarbamate (67.1 mg, 0.28 mmol, 49.3%) as a colorless oil that turned solid upon standing. LCMS 238.1 (M+H); 1H NMR (400 MHz, MeOH-d4) δ ppm 1.23 (d, J=6.57 Hz, 3H), 1.46 (s, 9H), 3.44 (dd, J=5.56, 1.77 Hz, 2H), 3.71-3.92 (m, 1H).

Provenance & Evidence