(3,4,5-Trifluorophenyl)boronic Acid (contains varying amounts of Anhydride) → 8-Propyl-3-(3,4,5-trifluorophenyl)-7,8,9,10-tetrahydrobenzo[c]chromen-6-one

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Reaction Steps

10 g (25.6 mmol) of 6-oxo-8-propyl-7,8,9,10-tetrahydro-6H-benzo[c]-chromen-3-yl trifluoromethanesulfonate, 4.50 g (25.6 mmol) of 3,4,5-trifluorobenzeneboronic acid, 10.6 g (38.4 mmol) of sodium metaborate octahydrate, 360 mg (0.51 mmol) of bis(triphenylphosphine)palladium chloride and 50 μl of hydrazinium hydroxide are dissolved in 15 ml of water and 250 ml of THF, and the mixture is refluxed overnight. Water is added to the batch, which is extracted three times with dichloromethane. The combined org. phases are dried over sodium sulfate, the solvent is removed under reduced pressure, and the residue is filtered through silica gel and recrystallised, giving 8-propyl-3-(3,4,5-trifluorophenyl)-7,8,9,10-tetrahydrobenzo[c]chromen-6-one.

Provenance & Evidence