To a suspension of sodium hydride (0.80 g, 33 mmol) in tetrahydrofuran (80 ml) was added a solution of (R)-phenylethanol (2.0 g, 17 mmol) in tetrahydrofuran (3 ml) cautiously over 10 min at 23° C. The mixture was stirred for 15 min, then 1-(4-chlorophthalazin-1-yl)-7-methoxy-naphthalen-2-ol (5.1 g, 15 mmol) was added portionwise. The resulting red suspension was stirred for 20 hrs at 23° C., then the solvent was removed under reduced pressure. The residue was dissolved in dichloromethane and poured into brine. The organic layer was separated and the aqueous layer was extracted two times with dichloromethane. The combined organic layers were dried over sodium sulfate and concentrated under reduced pressure. The residue was purified by flash chromatography on silica gel (hexane/EtOAc 4:1 to 1:1) to give 5.5 g (13 mmol) of the title compound as a 1:1 mixture of diastereomers, as a white foam.
