Hexafluoroacetone → E-methyl 6,6,6-trifluoro-5-hydroxy-5-(trifluoromethyl)hex-2-enoate

Participants

Reaction Steps

To a nitrogen-flushed, 150 mL steel reaction vessel with teflon-coated magnetic stirbar was added 30.0 g methyl 3-buteneoate (300 mmol, 1 eq.). Hexafluoroacetone (55.8 g, 336 mmol, 1.1 eq.) was condensed into the vessel at −78° C. The reaction vessel was sealed under 1 atmosphere of nitrogen and warmed to room temperature slowly. The reaction was heated at 160° C. for 16 hours after which the pressure had decreased dramatically. The vessel was cooled in an ice bath and the excess hexafluoroacetone was carefully vented through a saturated potassium hydroxide solution. The crude reaction mixture was vacuum distilled using a 6-inch, vacuum-jacketed vigereaux column with a short-path distillation head. The product was isolated at 75-80° C. (6 Torr) as a colorless liquid. A second distillation of the prefraction resulted in a total isolated yield of 55.4 g (69%) of E-methyl 6,6,6-trifluoro-5-hydroxy-5-(trifluoromethyl)hex-2-enoate (I).

Provenance & Evidence