Ethyl Acrylate → (E)-tert-Butyl 6-(3-ethoxy-3-oxoprop-1-enyl)-2-oxo-2,4-dihydro-1H-spiro[[1,8]naphthyridine-3,4'-piperidine]-1'-carboxylate

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Reaction Steps

Ethyl acrylate (2.3 mL, 21.2 mmol), diisopropylethylamine (3.7 mL, 21.2 mmol) and P(o-tolyl)3 (323 mg, 1.06 mmol) were successively added to a suspension of tert-butyl 6-bromo-2-oxo-2,4-dihydro-1H-spiro[[1,8]naphthyridine-3,4′-piperidine]-1′-carboxylate (2.10 g, 5.3 mmol) in propionitrile (20 mL) and dimethylformamide (5 mL) in a sealed tube. The resulting mixture was then purged with argon prior to the addition of palladium acetate (120 mg, 0.53 mmol). The mixture was purged with argon again and refluxed overnight. The reaction mixture was then filtered on Celite®. The filtrate was concentrated to dryness and the residue was solubilized in dichloromethane (100 mL). The resulting solution was washed with a saturated solution of ammonium chloride (100 mL), dried over sodium sulfate, filtered and concentrated to dryness. The residue was precipitated in dichloromethane/diethylether/pentane, the title product was obtained as an off-white solid (1.52 g, 70%).

Provenance & Evidence