[Br:1][C:2]1[CH:15]=[CH:14][C:5]([C:6]([C@H:8]2[CH2:10][C@H:9]2[C:11]([OH:13])=[O:12])=[O:7])=[CH:4][CH:3]=1.[CH3:16]OC(OC)(C)C.Cl>CO>[Br:1][C:2]1[CH:3]=[CH:4][C:5]([C:6]([C@H:8]2[CH2:10][C@H:9]2[C:11]([O:13][CH3:16])=[O:12])=[O:7])=[CH:14][CH:15]=1To a solution of cis-2-(4-bromobenzoyl)cyclopropanecarboxylic acid (10.6 g, 36.63 mmol) in MeOH (250 mL) was added 2,2-dimethoxypropane (9.54 g, 91.59 mmol) and HCl (4.0 M in dioxane, 3.50 mL). The resulting solution was stirred at 40° C. for 3 days, and then evaporated to dryness. The resulting residue was purified by flash chromatography (Biotage Flash 40M) using 15 to 25% ethyl acetate in hexanes to afford methyl cis-2-(4-bromobenzoyl)-cyclopropanecarboxylate (10.34 g, 99%). 1H NMR (400 MHz, CD2Cl2) δ 1.39 (m, 1H), 1.82 (m, 1H), 2.34 (m, 1H), 2.77 (m, 1H), 3.54 (s, 3H), 7.65 (m, 2H), 7.89 (m, 2H).
読み込み中…
