Acetic Acid → TERT-BUTYL 4-(INDOLIN-1-YL)PIPERIDINE-1-CARBOXYLATE

Participants

Reaction Steps

A solution of indoline 1 (2.0 g, 16.78 mmol), tert-butyl 4-oxopiperidine-1-carboxylate (3.68 g, 18.46 mmol) in dry 1,2-dichloroethane (30 mL) was treated with acetic acid (2.4 mL, 42.00 mmol) followed by NaBH(OAc)3 (5.34 g, 25.2 mmol) at 0° C. The resulting mixture was brought to room temperature and stirred for 3 h. The reaction was basified with 1 N NaOH solution (50 mL) and product was extracted into ethyl acetate (2×50 mL). The combined ethyl acetate layer was washed with brine (25 mL) and dried (Na2SO4). The solvent was evaporated and crude was purified by column chromatography (ethyl acetate:hexanes, 1:4) to obtain compound 2 (5.0 g, 99%) as a syrup. 1H NMR (CDCl3) δ 7.05 (t, 2H, J=7.8 Hz), 6.62 (t, 1H, J=7.2 Hz), 6.43 (d, 11, J=7.5 Hz), 4.25-4.20 (m, 2H), 3.55-3.46 (m, 2H), 3.35 (t, 2H, J=8.4 Hz), 2.95 (t, 2H, J=8.4 Hz), 2.77 (t, 2H, J=12.3 Hz), 1.81-1.77 (m, 2H), 1.63-1.51 (m, 2H), 1.47 (s, 9H); ESI-MS (m/z, %) 303 (MH+, 5), 247 (100).

Provenance & Evidence