Acetic Acid → 1-(1,4-Dioxaspiro[4.5]decan-8-yl)indoline

Participants

Reaction Steps

A solution of compound 1 (2.0 g, 16.78 mmol) and compound 2 (3.15 g, 20.139 mmol) in dry methanol (20 mL) was treated with acetic acid (2.4 mL, 42.00 mmol) followed by NaCNBH3 (1.26 g, 20.14 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 the crude product was purified by column chromatography (ethyl acetate:hexanes, 1:4) to obtain compound 3 (3.52 g, 81%) as a solid. 1H NMR (CDCl3) δ 7.06-7.02 (m, 2H), 6.59 (t, J=14.7 Hz, 1H), 6.42 (d, J=8.1 Hz, 1H), 3.46 (s, 4H), 3.46-3.35 (m, 3H), 2.93 (t, J=16.5 Hz, 2H), 1.87-1.60 (m, 8H). MS-ESI (m/z, %): 262 (8), 260 (MH+, 100), 120 (28).

Provenance & Evidence