3,4,5-Trimethoxybenzaldehyde → Methyl 1-(3,4,5-Trimethoxy-benzyl)-2,3-dihydro-1H-indole-5-carboxylate

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Reaction Steps

To a solution of 20 (300 mg, 1.69 mmol), 3,4,5-trimethoxybenzaldehyde (365 mg, 1.86 mmol) and dibutyltin dichloride (51 mg, 0.17 mmol) in THF (8 mL) was added phenylsilane (229 μl, 1.86 mmol). The mixture was stirred overnight at room temperature under nitrogen. Additional aldehyde and phenylsilane were added and the stirring continued until starting material was consumed. THF was evaporated in vacuum and the residue was purified by flash chromatography (eluent 20% EtOAc in hexane). The compound was further purified by re-crystallization in a mixture EtOAc/hexane and finally by a second flash chromatography (eluent 20% EtOAc in hexane) to give the title compound 21 (428 mg, 71%) as a white solid. 1H-NMR (DMSO) δ: 2.96 (t, J=8.4 Hz, 2H); 3.45 (t, J=8.7 Hz, 2H); 3.61 (s, 3H); 3.71 (s, 6H); 3.72 (s, 3H); 4.30 (s, 2H); 6.59 (s, 2H); 6.61 (d, J=8.4 Hz, 1H), 7.54 (d, J=1.6 Hz, 1H); 7.63 (dd, J=1.8, 8.4 Hz, 1H).

Provenance & Evidence