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

Participants

Reaction Steps

To a suspension of benzyl 4-oxo-1-piperazinecarboxylate (11.7 g, 50.3 mmol) in diethyl ether (100 ml) at −78° C. was added ethyl diazoacetate (6.84 ml, 65.3 mmol) followed by BF3.OEt2 (6.30 ml, 50.3 mmol). After 1 hour the reaction was raised to room temperature giving a clear yellow solution. A saturated aqueous solution of K2CO3 was added dropwise until no further gas evolution was observed. The organic layer was separated and washed with saturated aqueous K2CO3 (2×50 ml), dried (MgSO4), filtered and concentrated giving the title product as yellow oil (16.5 g, quant. yield). The product was used without further purification.

Provenance & Evidence