At −78° C., 2.35 ml (1.19 mmol) of a freshly prepared 0.5 M solution of bromo[4-(trifluoromethoxy)phenyl]magnesium in tetrahydrofuran are slowly added dropwise to a solution of 338 mg (990 μmol) of a 2:1 mixture of rac-5-(4-fluorophenyl)-7-isopropyl-2,2-dimethyl-4-oxochroman-6-carbaldehyde (Example 20A) and rac-5-(4-fluorophenyl)-7-n-propyl-2,2-dimethyl-4-oxochroman-6-carbaldehyde in 8 ml of tetrahydrofuran. The mixture is then allowed to thaw slowly to −20° C. and stirred at this temperature for 45 min. 10% strength sodium bicarbonate solution is then added, the mixture is extracted three times with ethyl acetate and the combined organic phases are washed with saturated sodium chloride solution. The organic phases are dried over magnesium sulfate, the solvent is then removed under reduced pressure and the residue is purified by preparative HPLC (method 1).
