Citric Acid → (2S)-2-phenyl-3-piperidone

Participants

Reaction Conditions

Reaction Steps

A solution of dimethyl sulfoxide (4.2 ml, 59 mmol) in dichloromethane (10 ml) was added dropwise to a stirred solution of oxalyl chloride ( 4.4 ml, 51 mmol) in dichloromethane (100 ml) at −70° C. over 10 min. After 10 min a solution of (2S,3S)-3-hydroxy-2-phenylpiperidine (10.5 g, 38.5 mmol) in dichloromethane (30 ml) was added dropwise at −70° C. over 10 min. The mixture was stirred an additional 10 min and triethylamine (15 ml, 108 mmol) added dropwise over 15 min. The reaction mixture was allowed to warm to −10° C. over 90 min and poured into a 10% aqueous solution of citric acid (200 ml). The phases were separated and the aqueous layer was extracted with dichloromethane (2×50 ml). The combined organic extracts were dried (Na2SO4) and concentrated to give crude (2S)-2-phenyl-3-piperidone which was immediately used in the next step.

Provenance & Evidence