Binap, (A+-)- → 2-tert-butyl-7-[(3S)-3-(dimethylamino)pyrrolidin-1-yl]-5-methyl-6-(3-nitrophenyl)-1,3-benzoxazole-4-carbonitrile

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Reaction Steps

(S)-(−)-2,2′-Bis(diphenylphosphino)-1,1′-binaphthyl (180 mg, 0.29 mmol) was dissolved in toluene (8 ml) under heat, cooled to room temperature, then palladium(II) acetate (43 mg, 0.193 mmol) was added, followed by stirring for 5 minutes. 7-Bromo-2-tert-butyl-5-methyl-6-(3-nitrophenyl)-1,3-benzoxazole-4-carbonitrile (I-18) (400 mg, 0.966 mmol), (3S)-3-(dimethylamino)pyrrolidine (306 μl, 2.42 mmol), sodium tert-butoxide (260 mg, 2.71 mmol), toluene (5 ml) were successively put into it, followed by stirring at 80° C. for 13 hours. After cooling, brine (10 ml), saturated sodium bicarbonate water (25 ml) were added to the reaction liquid, the product was extracted with chloroform (25 ml×2). The organic layer was washed with saturated brine (10 ml×2), then dried over anhydrous magnesium sulfate, concentrated under reduced pressure. The residue was purified twice by silica gel column chromatography (chloroform:methanol=100:1) to obtain a fraction containing the entitled compound (35.1 mg) as a dark brown solid. Not further purified, this was used in the next reaction.

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