Step 1: To a dry flask was added (S)-(-)-α,α-diphenylprolinol (0.30 g, 1.19 mmol) and anhydrous toluene (7 mL). The reaction system was placed under a nitrogen atmosphere by evacuating and displacing three times with nitrogen. A solution of borane tetrahydrofuran complex [BH3?THF; 1 M solution of THF] stabilized with 5 mM NaBH4 (0.35 mL, 3.56 mmol) was added slowly and dropwise at 30 °C, followed by stirring the clarified solution for 30 min.
Step 2: To the above stirred solution was added a solution of anhydrous toluene (1 mL) of 3-chloro-1-phenylpropan-1-one (1 g, 5.93 mmol). The reaction mixture was stirred at room temperature for 15 min before BH3?THF (6 mL, 61.44 mmol) was added within 3 min. After continued stirring for 9 min, the reaction flask was cooled in an ice bath, the reaction was quenched sequentially with methanol (10 mL), isopropanol (10 mL), and hydrochloric acid (3 mL), and filtered through a pad of diatomaceous earth. The filtrate was concentrated to dryness and the product was crystallized from hexane to give (R)-(+)-3-chloro-1-phenyl-1-propanol as a white fluffy solid (4.91 g).
Yield: 97%; Melting point: 57-59°C; [α]D25 = +25.7° (c 1, CHCl3); 1H NMR (400 MHz, CDCl3): δ 2.07-2.16 (m, 2H), 2.20-2.32 (m, 1H), 3.51-3.62 (m, 1H), 3.71-3.80 (m, 1H), 4.91 -4.98 (m, 1H), 7.37-7.43 (m, 5H); 13C NMR (400 MHz, CDCl3): δ 41.45, 41.73, 71.34, 125.80, 127.94, 128.69, 143.71; MS (EI+) m/z: 170 [M+], 172 [M+2], relative intensity ratio ca. is 3:1.
