Acetic acid, 2-(triphenylphosphoranylidene)-, ethyl ester → 4-tert-butoxycarbonylamino-3-(tert-butoxycarbonylamino-methyl)-but-2-enoic Acid Ethyl Ester

Participants

Reaction Conditions

Reaction Steps

To a solution of (3-tert-Butoxycarbonylamino-2-oxo-propyl)-carbamic acid tert-butyl ester (28 g, 97.0 mmol) dissolved in benzene (350 ml) was added (carbethoxymethylene)-triphenyl phosphorane (89 g, 0.26 mol) and the reaction mixture stirred for 16 hours at 45° C., under a N2 atmosphere. The mixture was concentrated and purified by column chromatography on silica gel (ethyl acetate:hexane, 1:3, v/v) to afford the product as a yellowish solid (26 g, 75%). 1H NMR (CDCl3) δ 1.43 (s, 18H), 1.59 (s, 3H), 3.90 (d, 2H, J=4.75 Hz), 4.11 (m, 4H,), 5.35 (m, 2H), 5.87 (s, 1H).

Provenance & Evidence