Chlorotrimethylsilane → 3-(1-Methylallyl)piperidine-1,3-dicarboxylic acid 1-tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

To a solution of piperidine-1,3-dicarboxylic acid 3-((E)-but-2-enyl)ester 1-tert-butyl ester (105.7 g) in tetrahydrofuran (1000 ml) cooled to −68° C. was added lithium hexamethyl disilazide (1.1M tetrahydrofuran solution, 411 ml). The reaction mixture was warmed to 0° C. over 20 minutes, stirred at the same temperature for additional 30 minutes, and then cooled to −68° C. again. To the mixture was added trimethylsilyl chloride (56.6 ml). The reaction mixture was warmed to room temperature over 2 hours, and stirred at the same temperature for additional 2 hours. After ice-cooling, to the mixture were sequentially added water (1000 ml) and 2M aqueous sodium hydroxide solution (136 ml), and the mixture was washed with n-hexane (1000 ml). The separated aqueous layer was acidified by 2M aqueous hydrochloric acid solution, and then extracted with ethyl acetate (800 ml). The organic layer was sequentially washed with water (700 ml) and saturated aqueous sodium chloride solution (400 ml), and the separated aqueous layer was extracted with ethyl acetate (600 ml) again. The combined organic layer was dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The resulting residue was slurry-washed with n-hexane/ethyl acetate solution (6/1, 700 ml) to give the titled compound (59.8 g). The filtrate was concentrated under reduced pressure, and the resulting residue was slurry-washed with n-hexane/ethyl acetate solution (4/1, 200 ml) again to give a solid (14.4 g). The solid was slurry-washed with n-hexane/ethyl acetate solution (5/1, 100 ml) again to give the titled compound (11.9 g). The resultant was combined to give the titled compound (71.7 g).

Provenance & Evidence