(4S)-4-Methyl-5,5-diphenyl-1,3-oxazolidin-2-one → (S)-(-)-1,1-Diphenyl-2-aminopropane

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Reaction Steps

A suspension of (S)-4-methyl-5,5-diphenyl-2-oxazolidinone (11) (3.52 g, 13.90 mmol) in MeOH/AcOH and a 10% Pd (148 mg, 1.39 mmol) on activated carbon was shaken for 45 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 (2M, 100 ml), stirred overnight at room temperature, made basic with NaOH pellets, and saturated with K2CO3. The organics were then extracted into diethyl ether (3×100 ml), dried over MgSO4/K2CO3 and concentrated under reduced pressure to obtain a crude product. Impurities were washed with AcOEt over silica gel by means of dry-flash column chromatography, and then further elution with a mixture of MeOH and AcOEt, ranging from 5% up to 30%, gave the title compound (12) (1.90 g, 65%) as a white solid. m.p. 76–77° C. [α]D25=−19.32 (c, 0.10765 in CHCl3). δH 1.04 (3H, d, 3J=6.30 Hz, CH3), 1.31 (2H, broad s, NH2), 3.55 (1H, d, J=9.90 Hz, CH—Ph2), 3.73 (1H, dq, 3J=6.30 and 10.20 Hz, CH—NH2), 7.10–7.40 (10H, m, Ar—H). δC 22.4 (CH3), 50.3 (CH—NH2), 62.4 (CH—Ph2), 126.5, 126.8, 128.2, 128.5, 128.7 and 129.0 (o-, m- and p-Ar), 143.3 and 143.7 (α-Ar). Anal. Calcld for C15H17NO: C 85.26; H 8.11; N 6.63. Found: C 85.10; H 8.08; N 6.36. ir 3343 (NH2). m/e (CI—NH3) 212 (MH+, 100%).

Provenance & Evidence