(R)-(+)-2,2′-Bis(diphenylphosphino)-1,1′-binaphthyl (70.2 mg, 113 μmol) was dissolved in toluene (2.7 ml) under heat, cooled to room temperature, then palladium(II) acetate (16.9 mg, 75.1 μmol) was added followed by stirring for 1 minute. 7-Bromo-2-tert-butyl-6-(3-methoxyphenyl)-5-methyl-1,3-benzoxazole-4-carbonitrile (I-20) (300 mg, 751 μmol), (3S)-3-(dimethylamino)pyrrolidine (114 μl, 902 μmol), sodium tert-butoxide (101 mg, 1.05 mmol), toluene (2.7 ml) were successively put into it, followed by stirring at 80° C. for 16 hours. After cooling, saturated sodium bicarbonate water (50 ml) was added to the reaction liquid, the product was extracted with chloroform (50 ml×2). The organic layer was washed with saturated brine (50 ml), dried over anhydrous magnesium sulfate, concentrated under reduced pressure. The residue was purified by silica gel column chromatography (chloroform:methanol=100:1), then further purified by silica gel thin-layer partitioning (chloroform:methanol:acetic acid=80:10:5) to obtain the entitled compound (7.3 mg, 2.2%) as a yellow semi-solid.
