N-Methoxy-N-methylbenzamide → 6-Benzoyl-3,3-dimethyl-2,3-dihydro-pyrrolo[3,2-b]pyridine-1-carboxylic acid tert-butyl ester

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Reaction Steps

n-Butyl lithium (5.0 mL of a 2.5 M solution in hexanes, 12 mmol) was added dropwise to a solution of 6-bromo-3,3-dimethyl-2,3-dihydro-pyrrolo[3,2-b]pyridine-1-carboxylic acid tert-butyl ester (3.27 g, 10.0 mmol) in diethyl ether (20 mL) at −78° C. The resulting orange slurry was stirred 30 minutes at this temperature, then a solution of N-methoxy-N-methyl-benzamide (2.3 mL, 15.0 mmol) in diethyl ether (10 mL) was added dropwise. The reaction was allowed to warm to room temperature and stirred 1 h further, then quenched with saturated aqueous ammonium chloride and the two layers were separated. The aqueous fraction was further extracted with EtOAc (2×20 mL). The combined organic fractions were dried over MgSO4, filtered and concentrated. The residue was purified by column chromatography (0-30% EtOAc/petrol) to give the title compound (2.4 g, 67%) as a yellow solid. MS: [M+H]+=353.

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