Boron trifluoride etherate → 1-tert-Butyl 4-ethyl 5-oxoazepane-1,4-dicarboxylate

Participants

Reaction Conditions

Reaction Steps

To a solution of tert-butyl 4-oxopiperidine-1-carboxylate (20.0 g, 100 mmol) in diethylether (60 mL) under nitrogen at −30° C., was added drop-wise a solution of BF3.Et2O (16.0 mL, 130 mmol) in ether (20 mL). After stirring for 30 min at −30° C., a solution of ethyl 2-diazoacetate (16.0 g, 140 mmol) in ether (20 mL) was added drop-wise to the reaction at −30° C. The resulting solution was stirred for 1 h at −30° C., then at room temperature for 2 h. The reaction was carefully quenched with 30% aqueous potassium carbonate (100 mL) and the resulting mixture was extracted with ethyl acetate (2×250 mL). The combined organic extracts were washed with brine (2×50 mL), dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography with ethyl acetate/petroleum ether (1/10) as the eluent to furnish 19 g (66%) of the title compound as a light yellow oil.

Provenance & Evidence