Sodium Carbonate → 5-Methyl-3-oxocyclohex-1-en-1-yl trifluoromethanesulfonate

Participants

Reaction Conditions

Reaction Steps

To a solution of 5-methylcyclohexane-1,3-dione (1.0 equiv.) in DCM (0.5 M) was added Na2CO3 (1.1 equiv.) and cooled to 0° C. Added Tf2O (1.0 equiv.) in DCM (5.0 M) dropwise over 1 hr at 0° C. under a nitrogen atmosphere. Upon addition, the reaction was stirred for 1 hr at room temperature (dark red solution). The solution was filtered and the filtrate was quenched by careful addition of saturated NaHCO3 with vigorous stirring until pH=7. The solution was transferred to a separatory funnel and the layers were separated. The organic layer was washed with brine, dried with Na2SO4, filtered, concentrated under vacuo and dried under high vacuum for 15 min to yield 5-methyl-3-oxocyclohex-1-enyl trifluoromethanesulfonate as light yellow oil in 78% yield. 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=0.86 min, LC=3.84 min. 1H-NMR (400 MHz, CDCl3) δ ppm: 6.05 (s, 1H), 2.70 (dd, J=17.2, 4.3, 1H), 2.53 (dd, J=16.6, 3.7, 1H), 2.48-2.31 (m, 2H), 2.16 (dd, J=16.4, 11.7, 1H), 1.16 (d, J=5.9, 3H).

Provenance & Evidence