Homoallyl bromide → Tert-butyl 4-but-3-enyl-3-oxopiperazine-1-carboxylate

Participants

Reaction Steps

Sodium hydride (60% dispersion in mineral oil, 42 mg, 1.05 mmol) was added at room temperature to a solution of 3-oxo-piperazine-1-carboxylic acid tert-butyl ester (200 mg, 1.00 mmol) in N,N-dimethylformamide (4 ml), then after 10 min a solution of 4-bromo-1-butene (148 mg, 1.10 mmol) in tetrahydrofuran (1 ml) was added dropwise. The reaction mixture was stirred for 3 h at room temperature, then another portion of 4-bromo-1-butene (40 mg, 0.30 mmol) was added dropwise, and the reaction mixture was heated at 50° C. for 18 h. After cooling, the reaction mixture was partitioned between water and heptane/ethyl acetate 1:1. The organic layer was washed with brine, dried (MgSO4), and evaporated. Chromatography (SiO2; heptane/ethyl acetate 1:1) afforded the title compound (217 mg, 81%). Colorless oil, MS (ISP)=255.2 (M+H)+.

Provenance & Evidence