Ethyl propiolate → HCID 57264429, compound

Participants

Reaction Conditions

Reaction Steps

n-Butyl lithium (2.28 ml, 1.6M solution in hexanes, 3.64 mmol) was added slowly to a cooled (-78° C.) solution of ethyl propiolate (0.370 ml, 3.64 mmol) in tetrahydrofuran (10 ml). the soluton was stirred for 10 min. at -78° C. after addition was complete then (2S)-1-tert-butoxycarbonyl-2-phenylpiperidin-3-one (Description 1, 1,0 g, 3.64 mmol) in tetrahydrofuran (10 ml) was added, the temperature being maintained below -75° C. The mixture was stirred for a further 10 min, then warmed to -60° C. when glacial acetic acid (1 ml) was added. The mixture was warmed to room temperature and poured into saturated aqueous sodium hydrogen carbonate (20 ml). The organic phase was separated and the aqueous phase was extracted with ethyl acetate (20 ml). The combined organic fractions were dried (Na2SO4) and the solvent was evaporated under reduced pressure. The residue was purified by flash column chromatography on silica gel, eluting with hexane/EtOAc (90:10), to give the title compound as a gum (801 mg, 59%), 1H NMR (250 MHz, CDCl3) δ7.50 (2H, m), 7.35 (3H, m), 5.49 (1H, s), 4.25 (2H, q, J 7.12 Hz), 4.15 (1H, m), 3.02 (1H, m), 2.23 (2H, m), 2.00 (2H, m), 1.78 (1H, m), 1.37 (9H, s), and 1.29 (3H, t, J 7.12 Hz), m/z (ES+) 374 (M+1).

Provenance & Evidence