Diethyl Ether → Isobutyl (E)-4-oxo-2-butenoate

Participants

Reaction Steps

To a suspension of pyridinium chlorochromate (100 g, 0.463 mol) in dichloromethane (350 ml), a solution of isobutyl (E)-4-hydroxycrotonate (50 g, 0.316 mol) in dichloromethane (150 ml) was added. The internal temperature gradually rose to 40° C. and stirring was continued for 2 hours without cooling. Diethyl ether (0.9 l) was added and the supernatant was decanted from the black gum. The insoluble residue was washed twice 300 ml portions of diethyl ether. The combined organic solutions were passed through a short pad of Florisil and the solvent was removed by distillation, to yield 45.3 g (91.6%) of the title compound, as a pale yellow oil, Rf=0.5 (silica gel plates, cyclohexane-ethyl acetate 6:4). NMR (CDCl3): deltaH =9.80 (ABX, 1H, CHO), 6.98 and 6.75 (ABX, JAB =15 Hz, 2H, CH=CH). MS (E.I., 70 eV, 1.5 mA) m/z=155 (M--H)+, 85 (M--C3H3O2)+.

Provenance & Evidence