Imidazole → Benzyl trans(+/-)-4-[(tert-butoxycarbonyl)amino]-3-{[tert-butyl(dimethyl)silyl]oxy}piperidine-1-carboxylate

Participants

Reaction Steps

tert-butyldimethylchlorosilane (6.51 g, 43.2 mmol) was added to a solution of (+/−)(3R,4R)-benzyl 4-((tert-butoxycarbonyl)amino)-3-hydroxypiperidine-1-carboxylate (prepared according to a published literature procedure: Fink, Brian, et al., WO 2005/066176, 10.1 g, 28.8 mmol) and imidazole (3.92 g, 57.6 mmol) in DMF (60 mL). The mixture was stirred at room temperature overnight. Ice water was added and the reaction mixture was extracted with ether twice, the combined extracts were washed with brine, dried over magnesium sulfate, filtered and concentrated in vacuo, the crude product was purified by flash chromatography on silica gel using an automated ISCO system (330 g column, eluting with 5-20% ethyl acetate/dichloromethane) to give (+/−)-(3R,4R)-benzyl 4-((tert-butoxycarbonyl)amino)-3-((tert-butyldimethylsilyl)oxy)piperidine-1-carboxylate (13.3 g,) as a white solid.

Provenance & Evidence