Trimethylsilyl triflate → 3-Bromo-4-oxo-piperidine-1-carboxylic acid benzyl ester

Participants

Reaction Conditions

Reaction Steps

To a cooled (0° C.) solution of N-benzyloxycarbonyl-4-piperidone (501, 27.3 g 117 mmol) in DCM (3 ml/mmol) was added DIPEA (25.5 ml, 146.2 mmol, 1.25 eg) and trimethylsilyl trifluoromethane sulfonate (25.4 ml, 141 mmol, 1.2 eg). The mixture was stirred for 30 minutes at 0° C. Next, N-bromosuccinimide (21.2 g, 119.3 mml, 1.02 eg) was added and stirring was continued for 16 hrs at room temperature. The reaction mixture was washed with 5% NaHCO3 and the organic layer was dried (MgSO4) and subsequently concentrated under reduced pressure. The resulting oil was purified by silica gel chromatography (diethyl ether/petroleum ether, 1/1 to 1/0, v/v, Rf 0.1) giving 502 in a yield of 90% as a yellow oil.

Provenance & Evidence