6704-31-0

2537-48-6

1123787-67-6

General procedure: preparation of intermediate compound (92). To a suspension of sodium hydride (4.12 g, 102.83 mmol) in 1,2-dimethoxyethane (DME, 120 mL), diethyl cyanomethylphosphonate (91) (16.2 mL, 99.8 mmol) was slowly added at 0-5 °C, keeping the reaction temperature below 5 °C. After stirring for 30 min at 0-5 °C, the mixture changed from a non-homogeneous phase to a homogeneous phase. Subsequently, a solution of DME (20 mL) of oxetan-3-one (90) (10.1 g, 83.2 mmol) was added dropwise to this homogeneous mixture at 5 °C. The reaction mixture was gradually warmed to room temperature and stirred overnight. Upon completion of the reaction, the reaction was quenched with water (250 mL) and extracted with ethyl acetate (200 mL, followed by 100 mL). The organic layers were combined, washed with brine (200 mL), dried over anhydrous magnesium sulfate (MgSO4), filtered, and the filtrate was concentrated to dryness under reduced pressure to afford 2-(oxetan-3-ylidene)acetonitrile (92) (8.0 g, 60% yield) as an oil, which was allowed to solidify. The product was analyzed by 1H NMR (300 MHz, DMSO-d6): δ 5.43-5.35 (m, 2H), 5.35-5.23 (m, 3H); 13C NMR (300 MHz, DMSO-d6): δ 163.57, 114.17, 9.88, 78.66, 78.53; IR (KBr): 2219 cm-1 ; elemental analysis (C5H5NO) calculated values: C, 63.15; H, 5.30; N, 14.73; measured values: C, 63.00; H, 5.36; N, 14.44.