Sodium hydride → 5-Isopropoxy-6-methoxy-1-methylene-1,2,3,4-tetrahydro-naphthalene

Beteiligte Stoffe

Reaktionsschritte

To a dry 250 mL 3-necked round bottom flask equipped with a reflux condenser and magnetic stir bar was added sodium hydride (1.09 g, 47.4 mmol) under nitrogen. 20 mL of anhydrous dimethylsulfoxide was added and the reaction mixture was heated to 70-75° C. for 30 min, until the evolution of hydrogen ceased. The reaction mixture turned green in color at this point, and then, the reaction mixture was cooled to room temperature and additional 15 mL of DMSO was added. Methyltriphenylphosphonium iodide (12.76 g, 31.57 mmol) was added in portions over a period of 30 min. 15 mL of additional DMSO was added and the reaction mixture was stirred for 20 minutes at room temperature. 35 (3.73 g, 15.8 mmol) dissolved in 5 mL of anhydrous DMSO was added to reaction mixture and the temperature was raised to 60-65° C., and stirred at that temperature for 8 h. The reaction mixture was poured into a 250 mL Erlenmeyer flask containing 75 mL ice and 75 mL of hexanes. The resulting mixture was stirred vigorously for 15 min, and then extracted with hexanes. The combined organic layers were washed DMSO:Water (1:1) and then dried over anhydrous sodium sulfate, filtered and evaporated under reduced pressure. Purification by flash column chromatography (silica gel 5:95, EtOAc:Hexanes) yielded 320 mg of 36 (10%). Rf—0.632, (30% ethylacetate in hexanes).

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