ethyl 6-iodo-2-trifluoromethyl-2H-1-benzopyran-3-carboxylate → ethyl 6-(pentafluoroethyl)-2-(trifluoromethyl)-2H-1-benzopyran-3-carboxylate

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Reaction Conditions

Reaction Steps

Potassium pentafluoropropionate (0.476 g, 2.35 mmol) was dissolved in toluene (6 mL) and DMF (6 mL). The vessel was fitted with a distilling head, and CuI (0.471 g, 2.474 mmol) was added with stirring. The reaction was heated to 120° C., removing the toluene by distillation. Ethyl 6-iodo-2-(trifluoromethyl)-2H-1-benzopyran-3-carboxylate (Example 72, Step 3) (0.469 g, 1.178 mmol) was added and the reaction was heated to 150° C. for 2 hours. The reaction was allowed to cool to room temperature and was partitioned between diethyl ether and H2O. The organic phase was dried over MgSO4, filtered and concentrated in vacuo. The resulting residue was purified by flash chromatography (silica gel 60, eluant: hexanes-ethyl acetate, 8:1) yielding, upon concentration of the solution, the desired ester (0.096 g, 21%) as a tan solid mass of suitable purity to use without further purification: 1H NMR (acetone-d6/300 MHz) 8.04 (s, 1H), 7.91 (d, 1H, J=2.2 Hz), 7.74 (dd, 1H, J=8.7, 2.2 Hz), 6.00 (q, 1H, J=7.1 Hz), 4.42−4.24 (m, 2H), 1.34 (t, 3H, J=7.3 Hz).

Provenance & Evidence