1049004-32-1

4-(Ethoxycarbonyl)cyclohexene-1-boronic acid, pinacol ester

Ethyl 4-((trifluoromethanesulfonyl)oxy)-3-cyclohexene-1-carboxylate (303 mg, 1 mmol) and pinacol ester of bis(boronic acid) (370 mg, 1.5 mmol) were added to KOAc (400 mg, 4 mmol) and Pd(dppf)Cl2 (10 mg, 0.05 mmol) in dioxane (5 mL). The reaction mixture was heated at 110 °C for 16 hours. After completion of the reaction, it was cooled to room temperature and the mixture was partitioned between EtOAc (10 mL) and saturated NaHCO3 solution (10 mL). The aqueous phase was extracted with EtOAc (10 mL × 2). The combined organic phases were washed with brine, dried over anhydrous MgSO4, filtered, and concentrated. Purification by fast chromatography (25% EtOAc in petroleum ether solution) afforded ethyl 4-boronic acid pinacol ester-3-cyclohexenecarboxylate (250 mg, 89% yield).LRMS m/z (M + H)+: 281 (measured value), 281 (calculated value).

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