Ethyl 2-oxo-3-(triphenyl-lambda~5~-phosphanylidene)propanoate → (E)-Ethyl 4-[2-(difluoromethoxy)phenyl]-2-oxobut-3-enoate

Temperatur

100 °C

A suspension of 2-(difluoromethoxy)benzaldehyde (295 g, 1714 mmol) and ethyl (triphenylphosphoranylidene)pyruvate (279.1 g, 742 mmol) was heated at 100° C. The dark red aldehyde immediately decolorized, and a yellow suspension was obtained, which slowly changed to a dark brown solution. 2-(Difluoromethoxy)benzaldehyde (52.5 g, 305 mmol) was added to the reaction mixture. Residual aldehyde was separated from the reaction mixture by distillation. The resulting mixture was stirred in heptane (500 mL) and diethyl ether (500 mL). The brown solid precipitate was filtered off, and washed with a 1:1 mixture of heptane and diethyl ether (3×250 mL). The filtrate was concentrated, yielding a brown oil (218.5 g). Purification by flash column chromatography (1.5 kg silica, 2-20% EtOAc in heptane, 125 mL/minute) gave the title compound (91 g) as a yellow oil. δH (CDCl3, 300 MHz) 1.42 (t, J 7.1 Hz, 3H), 4.40 (q, J 7.1 Hz, 2H), 6.59 (t, J 72.9 Hz, 1H), 7.20 (dd, J 7.3, 1.0 Hz, 1H), 7.28 (br t, J 7.6 Hz, 1H), 7.38 (d, J 16.3 Hz, 1H), 7.46 (dt, J 7.8, 1.7 Hz, 1H), 7.75 (dt, J 7.8, 1.6 Hz, 1H), 8.13 (d, J 16.3 Hz, 1H). MS [ES+] m/z 271 [M+H]+.

1. customa yellow suspension was obtained
2. customResidual aldehyde was separated from the reaction mixture by distillation
3. filtrationThe brown solid precipitate was filtered off
4. washwashed with a 1:1 mixture of heptane and diethyl ether (3×250 mL)
5. concentrationThe filtrate was concentrated

ORD-Eintrag

ord-183069226b6147e2be2e7d9045229455

Quelldatensatz

uspto-grants-2016_04

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US09309243B2