Reaktion #160756

Reaktionsgleichung

Tf2O

5-methylcyclohexane-1,3-dione

Na2CO3

→

5-methyl-3-oxocyclohex-1-enyl trifluoromethanesulfonate

Ausbeute 67.0%

Lösungsmittel

DCM

DCM

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONUpon addition
2. 2
   FiltrationThe solution was filtered and to the filtrate
3. 3
   workup.ADDITIONwas added saturated NaHCO3 (carefully),
4. 4
   Extraktionthen extracted the organics,
5. 5
   Trocknendried with brine
6. 6
   EinengenNa2SO4, and concentrated
7. 7
   SonstigeThe crude was purified via SiO2 column chromatography
8. 8
   Wascheneluting with DCM and hexanes (1:1) or alternatively via a neutral alumina plug
9. 9
   Wascheneluting with DCM

Vorschrift

To a solution of 5-methylcyclohexane-1,3-dione (1 equiv) in DCM (0.4M) was added Na2CO3 (1.0 equiv.) and cooled to 0° C. Added Tf2O (1.0 equiv.) in DCM (5M) dropwise over 1 hr at 0° C. under a nitrogen atmosphere. Upon addition, the reaction was stirred for 2 hr at room temperature (dark red solution). The solution was filtered and to the filtrate was added saturated NaHCO3 (carefully), then extracted the organics, dried with brine, then Na2SO4, and concentrated. The crude was purified via SiO2 column chromatography eluting with DCM and hexanes (1:1) or alternatively via a neutral alumina plug eluting with DCM to afford 5-methyl-3-oxocyclohex-1-enyl trifluoromethanesulfonate in 30% or 67% yield respectively. The triflate decomposes upon storage and should be used immediately for the next reaction. LC/MS=259.1/300.1 (M+H and M+CH3CN); Rt=0.94 min, LC=3.84 min.

Quelle