Triethylamine → (1S,4S)-5-(4-methoxy-3-nitro-phenyl)-2-oxa-5-aza-bicyclo[2.2.1]heptane

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Reaction Steps

To a stirred solution of 7.34 g (31.0 mmol) 4-bromo-2-nitro-anisole in 125 ml dioxane were added 5.25 g (37.2 mmol) (1S,4S)-(+)-2-aza-5-oxabicyclo[2,2,1]heptane hydrochloride, 1.109 g (3.10 mmol) 2-(dicyclohexylphosphino)biphenyl, 14.2 g (43.4 mmol) cesium carbonate, 696 mg (3.10 mmol) palladium (II) acetate and 5.65 ml (40.3 mmol) triethylamine. The mixture was heated at reflux for 24 h and then poured onto water and extracted three times with ethyl acetate. The combined organic phases were dried over sodium sulfate and concentrated in vacuo. Flash chromatography (1/99 methanol/dichloromethane) afforded 5.10 g (66%) (1S,4S)-5-(4-methoxy-3-nitro-phenyl)-2-oxa-5-aza-bicyclo[2.2.1]heptane as an orange oil. ES-MS m/e (%): 251 (M+H+, 100).

Provenance & Evidence