Acetic acid, 2-(triphenylphosphoranylidene)-, ethyl ester → tert-Butyl 4-(2-ethoxy-2-oxoethylidene)piperidine-1-carboxylate

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Reaction Conditions

Reaction Steps

A mixture of tert-butyl 4-oxopiperidine-1-carboxylate 165a (10.0 g, 50.2 mmol) and ethyl 2-(triphenylphosphoranylidene)acetate (26.2 g, 75.3 mmol) in toluene (200 mL) was stirred at 100° C. for 1 h. See FIG. 6. The mixture was concentrated and purified by column chromatography on silica gel (petroleum ether:ethyl acetate=10:1) to afford tert-butyl 4-(2-ethoxy-2-oxoethylidene)piperidine-1-carboxylate 165b (12.6 g, 93%) as a white solid. 1H NMR (400 MHz, CDCl3): δ 5.72 (s, 1H), 4.16 (q, J=7.2 Hz, 2H), 3.52-3.45 (m, 4H), 2.94 (t, J=5.6 Hz, 2H), 2.28 (t, J=5.6 Hz, 2H), 1.48 (s, 9H), 1.29 (t, J=7.6 Hz, 3H).

Provenance & Evidence