2,2,2-Trifluoro-1,1-ethanediol → Ethyl 2-methyl-4,4,4-trifluorocrotonate

A suspension of (carbethoxyethylidene)triphenylphosphorane (400 g, 1.10 mole) in tetrahydrofuran (600 mL) was treated with aqueous fluoral hydrate (71.5% w/w, 180 g, 1.10 mole) over a period of 4 hours. During the addition the reaction temperature rose to 45° C. and all of the solid dissolved to give a clear brown solution. The mixture was allowed to stand for 15 hours and was then heated under reflux for 3.5 hours. The solution was distilled at 2,700 Pa until the temperature in the distillation flask reached 140° C., giving ethyl (E)-2-methyl-4,4,4-trifluorobut-2-enoate as a solution in tetrahydrofuran (Solution A, 0.75 L, containing a maximum of 201 g of alkene); NMR (270 MHz, CDCl3): 1.3 (t, 3H, J=7Hz), 2.1 (br, s, 3H), 4.3 (q, 2H, J=7Hz) and 6.7 (m, 1H), (plus signals due to tetrahydrofuran).

1. additionDuring the addition the reaction temperature
2. customrose to 45° C.
3. dissolutionall of the solid dissolved
4. customto give a clear brown solution
5. temperaturewas then heated
6. temperatureunder reflux for 3.5 hours
7. distillationThe solution was distilled at 2,700 Pa until the temperature in the distillation flask
8. customreached 140° C.

ORD-Eintrag

ord-1755f01e8908469a8f896ec9b340c575

Quelldatensatz

uspto-grants-1994_02

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US05286740