Hydrochloric Acid → Benzyl 1-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrrole-2-carboxylate

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Reaction Steps

2-Benzyl 1-tert-butyl 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrrole-1,2-dicarboxylate (0.5 g) was dissolved in CH2Cl2 (1 mL) and then 4 N HCl in dioxane (1 mL) was added. The reaction was stirred at room temperature for 1 hour. The solvent was removed under vacuum. The residue was redissolved in DMF (4 mL). To the resulting solution was added NaH (60% dispersion in mineral oil, 0.08 g, 2.0 mmol) at 0° C. The reaction mixture was stirred at 0° C. for 10 minutes. Methyl iodide (0.11 mL, 2.0 mmol) was added and the reaction was stirred at room temperature for 3 hours. The reaction was quenched with sat. NH4Cl solution and then diluted with EtOAc. After separation of layers, the organic phase was washed with water (twice) and brine; dried over Na2SO4. The solvent was removed to provide the desired crude product which was used in the next step without further purification. LCMS calculated for C19H25BNO4 (M+H)+: m/z=342.2. found: 342.2.

Provenance & Evidence