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温度

0 °C

n-Butyllithium (2.5 M solution in hexanes, 7.1 mL, 17.75 mmol) was slowly added (0.2 mL/min) to a solution of 2,2,6,6-tetramethylpiperidine (3 mL, 17.75 mmol) in dry diethyl ether (16 mL) at −30° C. under argon atmosphere. The reaction mixture was stirred at 0° C. for 30 minutes before being cooled down to −78° C. and a solution of 3-methoxypyridazine (Preparation 8a, 0.85 g, 7.72 mmol) in dry diethyl ether (4 mL) was slowly added (0.03 mL/min). The reaction mixture was stirred at this temperature for 10 additional minutes before the addition of tributylchlorostannane (2.5 mL, 9.22 mmol). After stirring at −78° C. for 45 minutes, a mixture of diethyl ether and aqueous saturated solution of ammonium chloride (15 mL/5 mL) was added and the temperature was allowed to warm up to ambient temperature. Additional diethyl ether (300 mL) was then added to the mixture and the organic layer was separated, washed with saturated aqueous solution of ammonium chloride, dried over magnesium sulphate and the solvent removed under reduced pressure. The residue was purified by flash chromatography (100% hexanes to 1:1 hexanes/diethyl ether) to give the title compound (0.31 g, 10%) as a pale yellow oil.

1. temperaturebefore being cooled down to −78° C.
2. stirringAfter stirring at −78° C. for 45 minutes
3. additionwas added
4. temperatureto warm up to ambient temperature
5. customthe organic layer was separated
6. washwashed with saturated aqueous solution of ammonium chloride
7. dry with materialdried over magnesium sulphate
8. customthe solvent removed under reduced pressure
9. customThe residue was purified by flash chromatography (100% hexanes to 1:1 hexanes/diethyl ether)