Potassium Phosphate, Tribasic → 5-(4-Fluorophenyl)-7-isopropyl-4-oxo-3,4-dihydrospiro[chromen-2,1'-cyclobutane]-6-carbaldehyde

Participants

Reaction Steps

Under argon, 4.00 g (9.84 mmol) of 6-formyl-7-isopropyl-4-oxo-3,4-dihydrospiro[chromen-2,1′-cyclobutan]-5-yl trifluoromethanesulfonate (Example 50A), 1.79 g (12.8 mmol) of 4-fluorophenyl-boronic acid, 3.55 g (16.73 mmol) of tripotassium phosphate and 1.25 g (1.08 mmol) of tetrakis(triphenylphosphine)palladium(0) are initially charged and the apparatus is flushed by repeated evacuation and venting with argon. 100 ml of abs. dioxane are then added, the apparatus is closed and the mixture is heated under reflux. After stirring overnight, the mixture is cooled and filtered through a layer of silica gel, the filter cake is washed thoroughly with ethyl acetate and the filtrate is concentrated. The residue is adsorbed on silica gel and chromatographed on a silica gel column (mobile phase: cyclohexane→cyclohexane/ethyl acetate 25:1). The crude product obtained is triturated with hot petroleum ether and cooled slowly, and the precipitate is filtered off with suction. This gives 3.2 g of the target compound in a purity of about 90%.

Provenance & Evidence