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

Participants

Reaction Steps

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).

Provenance & Evidence