Diisopropylamine → tert-Butyl 3-(2-tert-butoxy-2-oxoethyl)-4-oxopiperidine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a solution of diisopropylamine (13.5 ml, 96 mmol) in THF (300 ml) at −78° C. was added dropwise n-BuLi (2.5M in Hex, 32 ml). The mixture was warmed to −10° C. and re-cooled to −78° C. A solution of 4-oxo-piperidine-1-carboxylic acid tert-butyl ester (10 g, 50 mmol) in THF (50 ml) was then added dropwise and the mixture stirred at −78° C. for another 15 min. A solution of tert-butyl bromoacetate (12.6 ml, 85 mmol) in THF (30 ml) and HMPT (5 ml) was then added dropwise and the mixture stirred at −78° C. for 4 h and then gradually warmed to rt. The mixture was taken up in sat. aq. NH4Cl and extracted with EA. The yield after work up and chromatography (eluent Hex/EA 4:1) was 7.6 g (50.6%; yellowish oil).

Provenance & Evidence