159635-22-0

159635-49-1

159635-22-0

General procedure for the synthesis of tert-butyl 3-hydroxy-4-methylene-piperidine-1-carboxylate from tert-butyl 4-methylene-piperidine-1-carboxylate: selenium dioxide (2.81 g, 0.0253 mol) was suspended in dichloromethane (150 mL) and cooled to 0 °C. Tert-butyl hydroperoxide (13.9 mL, 0.101 mol, 70% aqueous solution) was slowly added and the mixture was stirred at 0°C for 30 minutes. Subsequently, a solution of dichloromethane (20 mL) of tert-butyl 4-methylene piperidine-1-carboxylate (10.0 g, 0.0507 mol) was added and the reaction mixture was continued to be stirred at 0 °C for 60 min, and then warmed up to 23 °C for 16 hours. Upon completion of the reaction, the reaction was quenched by the addition of ice and 10% aqueous sodium bisulfite (150 mL). The organic layer was separated and the aqueous layer was extracted with dichloromethane. The organic phases were combined, dried with anhydrous magnesium sulfate, filtered and concentrated. Purification by silica gel column chromatography (elution gradient: 25% ethyl acetate-hexane to 50% ethyl acetate-hexane) afforded the target product tert-butyl 3-hydroxy-4-methylene-piperidine-1-carboxylate (5.26 g, 0.0247 mol, 49% yield) as a yellow oil. Mass spectrum (FAB-MS): m/e 214.