Triethylamine → tert-Butyl 4-formylpiperidine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a cooled (0° C.) solution of 4-hydroxymethylpiperidine-1-carboxylic acid, 1,1-dimethylethyl ester (Example 36; 0.82 g, 3.8. mmol) and triethylamine (2.75 mL, 19.76 mmol) in dichloromethane (20 mL) was added sulfur trioxide pyridine complex (2.42 g, 15.2 mmol) in dimethylsulfoxide (10 mL) in three portions and the reaction was stirred at 0° C. for 3.5 h. Examination of the reaction by tlc indicated that some starting alcohol remained, so an additional quantity of sulfur trioxide pyridine complex (1.21 g, 7.6 mmol) in dimethylsulfoxide (5 mL) was added and the reaction was allowed to proceed for another 2 h at 0° C. The reaction mixture was partitioned between saturated sodium bicarbonate solution (60 mL) and diethyl ether/hexane (1:2, 125 mL) and the separated aqueous phase was re-extracted with diethyl ether/hexane (1:2, 2×50 mL). The combined organic extracts were washed with a 1M sodium dihydrogen phosphate solution (50 mL) and with brine (50 mL), then were dried (MgSO4), filtered and evaporated in vacuo. The resulting residual material was chromatographed over silica gel (25% ethyl acetate/petroleum ether) to give 4-formylpiperidine-1-carboxylic acid, 1,1-dimethylethyl ester (0.492 g, 61% yield) as a colorless oil.

Provenance & Evidence