Reaction #985305

Reaction equation

3,3-Diethoxy-1-propyne

Ethyl trifluoroacetate

n-butyllithium

hexane

→

orange oil

Yield 31.5%

5,5-Diethoxy-1,1,1-trifluoro-pent-3-yn-2-one

Yield 31.5%

Solvents

THF

Conditions

Workup

1. 1
   Temperatureto warm to −30° C.
2. 2
   Temperaturecooled again to −70° C
3. 3
   Otherrose to −50°
4. 4
   workup.STIRRINGthen stirred
5. 5
   Temperaturewithout cooling until −30° C.
6. 6
   Otherquenched with sat. NH4Cl solution (20 mL)
7. 7
   ExtractionExtraction

Procedure

3,3-Diethoxy-1-propyne (10 mL, 70 mmol) was dissolved under argon in THF (200 mL) and cooled to −70° C. Then a 1.6 M solution of n-butyllithium in hexane (48 mL, 77 mmol) was added slowly at −70° C., then allowed to warm to −30° C. and stirred at −30° C. for 30 min, then cooled again to −70° C. Ethyl trifluoroacetate (9.2 mL, 77 mmol) was added in one portion at −70° C. (the temperature rose to −50°) then stirred without cooling until −30° C. was reached, then quenched with sat. NH4Cl solution (20 mL). Extraction: 2×AcOEt, 1× sat. NH4Cl sat., 1× sat. NaCl. Chromatography on silica gel in heptane/ethyl acetate 5:1 afforded 4.94 g (31%) of an orange oil. GC/MS: m/z=223 (M−H).

Source