Binap, (A+-)- → (S)-N-[4-(trifluoromethyl)phenyl]-3-hydroxypentanoic acid amide

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Reaction Conditions

Reaction Steps

N-[4-(trifluoromethyl)phenyl]-3-oxopentanoic acid amide 1.30 g (5.0 mmol) produced in Example 1 and ((S)-BINAP)RuBr2 50.0 mg (0.057 mmol) (BINAP denotes 2,2′-bisdiphenylphosphino-1,1′-binaphthyl. It was prepared according to the method described in Tetrahedron Asymmetry, 1994,5,675) were mixed with 20 mL of a methanol-water (10/1 in volume) solution. Hydrogen replacement was carried out three times and after the reaction solution was heated to 60° C., reaction was carried out under hydrogen pressure (3.0 kg/cm2) for 12 hours. After releasing hydrogen, the solution was concentrated under reduced pressure and purifying on silica gel chromatography was carried out to obtain (S)-N-[4-(trifluoromethyl)phenyl]-3-hydroxypentanoic acid amide as a white solid (1.23 g, isolated yield: 95%). The optical purity of the product was determined by HPLC analysis (column; Daicel Chiral Pack AD-H 4.6×250 mm: eluent; hexane/isopropanol=90/10: flow rate; 1.0 mL/min: column temperature; 30° C.: detector; UV 210 nm: retention time; (S) antipode=12.0 minutes, (R) antipode=9.3 minutes) to be 84.7% ee. 1H-NMR (CDCl3, 400 MHz/ppm): δ 1.00 (3H, t), 1.5-1.7 (2H, br), 2.50 (1H, dd), 2.59 (1H, dd), 2.75 (br, 1H), 4.06 (1H, m), 7.57 (2H, d), 7.64 (2H, d), 8.21 (1H, br)

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