(4S)-4-Benzyl-5,5-diphenyl-1,3-oxazolidin-2-one → (S)-(-)-1-Benzyl-2,2-diphenylethylamine

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Reaction Steps

A solution of (S)-4-benzyl-5,5-diphenyl-2-oxazolidinone (7) (940 mg, 2.85 mmol) in MeOH/AcOH and a 10% Pd (121 mg, 1.14 mmol) on activated carbon was shaken for 43 h under 4–5 atm pressure of hydrogen at room temperature. The catalyst was filtered off over Hyflo Super Cell and organic solvents were evaporated under reduced pressure. The resulting residue was treated with HCl, stirred for 2 h at room temperature, made basic with NaOH pellets, and saturated with K2CO3 and NaCl. Organics were then extracted into dichloromethane (4×50 ml), dried over MgSO4/K2CO3 and concentrated under reduced pressure to obtain a crude product. Purification over silica gel, eluting with a 3:7 and 4:6 mixture of AcOEt and petroleum ether, gave the title compound (8) (584 mg, 71%) as a light-brown solid. m.p. 71–72° C. [α]D25=−8.03° (c, 0.1046 in CHCl3). δH 1.21 (2H, broad s, NH2), 2.29 (1H, dd, 3J=9.6 Hz, 2J=13.5 Hz, CH2—Ph), 2.79 (1H, dd, 3J=2.1 Hz, 2J=13.2 Hz, CH2—Ph), 3.71 (1H, d, 3J=9.9 Hz, CH—Ph2), 3.81 (1H, ddd, 3J=2.7, 9.9 and 12.6 Hz, CH—NH2), 7.06–7.33 (15H, m, Ar—H), δC 41.9 (CH2—Ph), 55.7 and 59.7 (CH—Ph2 and CH—NH2), 126.3, 126.5, 126.6, 128.1, 128.2, 128.4, 128.7, 128.8 and 129.1 (o-, m- and p-Ar), 139.7, 142.6 and 143.1 (α-Ar). ir 3387 (NH2). m/e (CI—NH3) 288 (MH+, 100%).

Provenance & Evidence