Carbon Dioxide → 3-(Cycloprop-2-enecarbonyl)-3H-benzoxazol-2-one

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反応手順

A flame-dried 100 mL round bottomed flask containing 6 (84 mg, 1.0 mmol) and 20 mL of THF was chilled by a cold bath at −30° C. (dry ice/30% ethanol in ethylene glycol). The mixture was allowed to stir under nitrogen atmosphere. Distilled triethylamine (0.36 g, 0.50 mL, 3.5 mmol) and 1-adamantyl chloride (238 mg, 1.2 mmol) were added sequentially, and stirring at −30° C. was continued for one hour. LiCl (0.21 g, 5.0 mmol) was added. After five minutes, 2-benzoxazolinone (203 mg, 1.50 mmol), and 4-dimethylamino pyridine (13 mg, 0.10 mmol) were added. The whole reaction mixture was allowed to stir overnight at room temperature. The solvents were removed under reduced pressure, and the residue was partitioned between 20 mL of CH2Cl2, and 20 mL water. The aqueous layer was extracted twice with 20 mL portions of CH2Cl2, and the combined organics were dried (Na2SO4), filtered, and concentrated. The residue was chromatographed on silica gel. The eluent was 1:3:6 CH2Cl2:ethyl acetate:hexane. The yield of 27 was 161 mg (0.80 mmol, 80%). Compound 27 is a white solid.

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