2-Cyclohexen-1-one → 3-Butylcyclohexanone

関与物質

反応条件

反応手順

A THF (5 mL) suspension of CuBr.Me2S (26.3 mg, 0.128 mmol) was treated with 1.0 equiv of n-BuLi at -78° C. under an argon atmosphere. The mixture was allowed to warm up slightly with the formation of a bright yellow solid. The mixture was again cooled to -78° C. and treated with Li(CHIRAMT) formed from compound 4 (85.8 mg, 0.261 mmol) and n-BuLi (1.0 equiv). The yellow slurry was stirred with gradual warming until a homogeneous burgundy solution was obtained. In the case of R=Me, a homogeneous mixture was not obtained even after prolonged stirring at room temperature, and it was evident that unreacted (CuMe)n was still present. The solution was cooled to -78° C. and THF (8 mL each) solutions of n-BuMgCl (25.0 equiv) and cyclohexenone (0.3068 g, 3.19 mmol) were added dropwise and simultaneously over a 5 min period. The resulting reaction mixture was stirred for an additional 10 min at -78° C., quenched with saturated aqueous NH4Cl solution (7 mL), and worked up as described in the previous section. Pure 3-butylcyclohexanone (0.4617 g, 94%) was obtained as checked by glc.

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