ethyl 2-bromocyclopropane-1-carboxylate

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a suspension of NaH (0.355 g, 14.0 mmol) in 100 ml of dry N,N-dimethylformamide was added slowly 5-benzyloxyindole (3.0 g, 13.4 mmol). When the evolution of H2 ceased, ethyl 2-bromocyclopropanecarboxylate(2.85 g, 0.0148 mol), as prepared in the preceding step, was added to the mixture and the reaction was refluxed for a period of 17 h under argon. Then the reaction was cooled down at ambient temperature and quenched carefully with water. After evaporation of the solvent under vacuum, the crude product was purified by flash chromatography on silica gel to obtain the title compound (3.45 g, 77%). 1H NMR (400 MHz, CDCl3) δ 1.34 (t, 3H, J=7.1 Hz), 1.62 (m, 1H), 1.73 (m, 1H), 2.14 (m, 1H), 3.78 (m, 1H), 4.24 (c, 2H, J=7.1 Hz), 5.10 (s, 2H), 6.36 (dd, 1H, J=0.7, 3.2 Hz), 6.98 (dd, 1H, J=2.4, 8.8 Hz), 7.04 (d, 1H, J=3.2 Hz), 7.14 (d, 1H, J=2.4 Hz), 7.38 (m, 4H), 7.45 (m, 2H). was added to the mixture the reaction was refluxed for a period of 17 h under argon quenched carefully with water After evaporation of the solvent under vacuum the crude product was purified by flash chromatography on silica gel