反应详情

NaBH4 (36 g, 1.0 mol) was added in portions to a solution of (S)-1-tert-butyl 2-ethyl 5-oxopiperidine-1,2-dicarboxylate (250 g, 0.92 mol) in EtOH (1500 mL) at −40° C. The reaction mixture was then stiffed at −40° C. for 0.5 hr then quenched with 10% HOAc solution. After diluting with water, the mixture was extracted with DCM three times. The combined organic layer was concentrated in vacuum and purified by silica gel column chromatography (1:1 petroleum ether/EtOAc) to afford (2S,5S)-1-tert-butyl 2-ethyl 5-hydroxypiperidine-1,2-dicarboxylate (205 g, 80%) as a yellow oil.

1. customthen quenched with 10% HOAc solution
2. additionAfter diluting with water
3. extractionthe mixture was extracted with DCM three times
4. concentrationThe combined organic layer was concentrated in vacuum
5. custompurified by silica gel column chromatography (1:1 petroleum ether/EtOAc)