反应详情

To a solution of LDA (prepared by adding n-butyllithium (20.0 mL, 49.3 mmol) to diisopropylamine (5.16 mg, 51.0 mmol) in THF (40 mL) at 0° C., stirred for 30 min) was added 1-tert-butyl 4-methyl piperidine-1,4-dicarboxylate (4.00 g, 16.4 mmol) in TMEDA (15 mL, 99 mmol) drop-wise via syringe pump at −78° C. for 10 min. The mixture was stirred at the same temperature for 30 min, then tert-butyl (2-oxoethyl)carbamate (8.11 g, 51.0 mmol) in THF (20 mL) was added slowly by syringe pump for 15 min. The mixture was stirred at −78° C. for 30 min, quenched with saturated NH4Cl at −78° C., warmed up to rt and diluted with EtOAc (200 mL). The organic layer was separated, and the aqueous layer was extracted with EtOAc (100 mL). The combined organic layers were washed with brine, dried (MgSO4), and concentrated. The residue was purified by column chromatography (80 g, silical gel, MeOH/DCM, gradient 0-10%, monitor at 210 nm) to afford title compound. LC/MS: [(M+1)]+=403

1. stirringThe mixture was stirred at −78° C. for 30 min
2. customquenched with saturated NH4Cl at −78° C.
3. additiondiluted with EtOAc (200 mL)
4. customThe organic layer was separated
5. extractionthe aqueous layer was extracted with EtOAc (100 mL)
6. washThe combined organic layers were washed with brine
7. dry with materialdried (MgSO4)
8. concentrationconcentrated
9. customThe residue was purified by column chromatography (80 g, silical gel, MeOH/DCM, gradient 0-10%, monitor at 210 nm)