反应详情

4-(2-Diazo-acetyl)-piperidine-1-carboxylic acid benzyl ester (44 g, 0.15 mol) in EtOAc (300 mL) was cooled to 0° C. The solution was treated with 33% HBr/HOAc (75 mL, 0.42 mol) over 15 min and stirred at ambient temperature for 2 hours. The mixture was slowly treated with saturated NaHCO3 solution (300 mL) until pH was neutral or slightly basic and filtered. The solution was dried over MgSO4 and subjected to a 330 g SiO2 COMBIFLASH column (0-100% EtOAc-hexanes gradient) to afford 4-(2-bromo-acetyl)-piperidine-1-carboxylic acid benzyl ester (38.1 g, 81%): MS (ESI) m/z 341 [M+H]+.

1. filtrationslightly basic and filtered
2. dry with materialThe solution was dried over MgSO4