反应详情

To a solution of trans-2-(4-bromobenzoyl)cyclobutanecarboxylic acid (8.2 g, 28.94 mmol) in MeOH (250 mL) was added 2,2-dimethoxypropane (3.65 g, 35.02 mmol) and HCl (4.0 M in dioxane) (2.0 mL). The resulting solution was stirred at rt for 3 days, and then evaporated to dryness. The resulting residue was purified with flash chromatography (Biotage Flash 40M) using 4 to 11% ethyl acetate in hexanes to afford methyl trans-2-(4-bromobenzoyl)cyclobutanecarboxylate (6.21 g, 78%). 1H NMR (400 MHz, CD2Cl2) δ 2.14–2.39 (m, 4H), 3.62 (m, 1H), 3.68 (s, 3H), 4.24 (m, 1H), 7.63 (m, 2H), 7.80 (m, 2H).

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2. customThe resulting residue was purified with flash chromatography (Biotage Flash 40M)