Iodopentafluoroethane → 1-(5-Bromo-pyridin-3-yl)-4,4,5,5,5-pentafluoro-pent-1-en-3-one

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Reaction Steps

To a saturated solution of pentafluoroiodoethane (0.84 M, in diethyl ether) (108.0 mL, 91.0 mmol), was slowly added a solution of methyllithium/lithium bromide (1.5 M, in diethyl ether) (61.0 mL, 91.0 mmol) under nitrogen atmosphere at −78° C. The reaction mixture was stirred for 20 minutes and then a solution of 3-(5-bromo-pyridin-3-yl)-N-methoxy-N-methyl-acrylamide (8.2 g, 30.3 mmol, in diethyl ether/tetrahydrofuran 50.0 mL/150.0 mL) prepared in Step 2 was slowly added thereto at −78° C. The reaction mixture was stirred at room temperature for 2 hours, quenched with distilled water, acidified by a 10% potassium hydrogen sulfate solution (pH=5), and then extracted with ethyl acetate. The extract was washed with a saturated solution of sodium hydrogen carbonate, dried on anhydrous magnesium sulfate, and then concentrated under reduced pressure to give a yellow liquid residue. The resulting residue was purified by silica gel column chromatography (eluent: ethyl acetate/n-hexane=1/5) to give 2.9 g of the titled compound as a yellow solid.

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