Allyl bromide → 1-tert-Butyl 4-ethyl 4-(prop-2-en-1-yl)piperidine-1,4-dicarboxylate

Participants

Reaction Conditions

Reaction Steps

n-Butyllithium (15% solution in n-hexane; 24.5 mL, 0.057 mol) is added to a stirred solution of diisopropyl amine (8.38 mL, 0.059 mol) in tetrahydrofuran (140 mL) at −70° C. under an atmosphere of nitrogen and stirred for 30 minutes. A solution of piperidine-1,4-dicarboxylic acid-1-tert-butyl ester-4-ethyl ester (8.0 g, 0.0311 mol) in tetrahydrofuran (20 mL) is introduced at −70° C. Hexamethyl phosphoramide (15 mL) is added and reaction mixture is allowed to stir till the temperature reaches at −45° C. Reaction mixture again cooled to −70° C., allyl bromide (13.5 mL, 0.155 mol) is added and stirred for 1 hour. Saturated aqueous solution of ammonium chloride (100 mL) is added slowly into the reaction mixture at −30° C. and stirred for 10 minutes. It is extracted with ethyl acetate (3×60 mL). Combined organic layer is washed with brine solution (1×30 mL) and dried over sodium sulfate. Removal of solvent under reduced pressure gives a viscous liquid which is purified by column chromatography (silica gel 230-400, n-hexane:ethyl acetate, 9:1) to furnish 4-allyl piperidine-1,4-dicarboxylic acid-1-tert-butylester-4-ethyl ester.

Provenance & Evidence