Dimethyl Sulfoxide → 1-Tert-butyl 3-methyl 5-oxopiperidine-1,3-dicarboxylate

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Reaction Steps

To a solution of dimethylsulfoxide (2.2 mL, 41.46 mmol) in dry dichloromethane (50 mL) at −78° C. was added dropwise at oxalyl chloride (1.57 mL, 18.2 mmol). After 10 min, a solution of 1-tert-butyl 3-methyl 5-hydroxypiperidine-1,3-dicarboxylate (4.3 g, 16.59 mmol) in dichloromethane was added dropwise. After 15 min, triethylamine (6.92 mL, 49.7 mmol) was added dropwise and the reaction mixture was then allowed to warm to room temperature. After 3 h, the mixture was diluted with dichloromethane and washed with water, dried over sodium sulfate, filtered and concentrated under reduced pressure to afford 1-tert-butyl 3-methyl 5-oxopiperidine-1,3-dicarboxylate (4.2 g) which was used in the next step without further purification.

Provenance & Evidence