2,3-Dichloro-5,6-dicyano-1,4-benzoquinone → 1H-Pyrrolo[2,3-B]pyridine, 5-bromo-1-[(1,1-dimethylethyl)dimethylsilyl]-

Participants

Reaction Steps

DDQ (about 380 mg, 1.68 mmol) was added in portions to a solution of 4 (525 mg, 1.68 mmol) in a mixture of CH2Cl2 (90 mL) and 0.2 M phosphate buffer pH 7 solution (910 μL) until full consumption of the starting material (TLC). Then, saturated aqueous NaHCO3 solution (22 mL) was added, and the reaction mixture stirred for 0.5 h. The organic layer was separated and the aqueous layer was extracted with CH2Cl2 (3×20 mL). The combined organic solutions were dried (MgSO4), concentrated and purified by SGC with hexane:CH2Cl2 as eluent (in gradient up to 20% CH2Cl2) to give 26 (505 mg, 97%) as a clear oil; 1H NMR (400 MHz, CDCl3) δ 0.62 (s, 6H), 0.93 (s, 9H), 6.47 (d, J=3.5 Hz, 1H), 7.24 (d, J=3.5 Hz, 1H), 7.97 (d, J=2.2 Hz, 1H), 8.28 (d, J=2.2 Hz, 1H).

Provenance & Evidence