Triethylamine → Benzyl 4-Hydroxy-1-piperidinecarboxylate

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Reaction Steps

A solution of 4-hydroxypiperidine (25.0 g, 0.247 mol) in methylene chloride (2000 mL) was cooled to 0° C. under nitrogen with overhead stirring. Triethylamine (86.1 mL, 0.618 mol, 2.5 eq) was added followed by benzyl chloroformate (35.3 mL, 0.247 mol, 1.0 eq). The reaction was warmed to room temperature over 1 h and maintained at this temperature for 5 h. A significant amount of amine hydrochloride precipitates in the course of the procedure. The organic phase was washed with 3N HCl (3×250 mL), dried over anhydrous sodium sulfate and filtered. The solvent was removed in vacuo to yield 47.0 g (81%) of the title compound as an oil. The product did not require any addition purification prior to the Swern oxidation. TLC analysis (Rf 0.17, 50% ethyl acetate in hexane). MS (CI, CH4) m/z 236 (M+1,42), 218 (4), 192 (10), 181 (9), 174 (15), 91 (100)

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