Isopropanol → 4-Methyl-benzenesulfinic acid[2-(4-chlorophenyl)-1-cyano-2-methyl-propyl]-amide

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Reaction Conditions

Reaction Steps

The diethyl aluminum cyanide (43.5 mL of a 1.0M solution in toluene, 43.5 mmol) was added to isopropanol (28.9 mL, 377 mmol) and stirred at 10° C. for 15 minutes. This solution was cannulated into the (R)-4-methylbenzenesulfinic acid [2-(4-chlorophenyl)-2-methyl-propylidene]-amide (9.28 g, 29.0 mmol) as a solution in 290 mL of THF at −78° C. This solution was allowed to stir for 15 minutes at −78° C. then allowed to warm slowly to room temperature overnight. The solution was quenched with the addition of diluted NaHCO3 solution and extracted with ethyl acetate. The combined organic was washed with brine, separated, dried over Na2SO4, filtered, and concentrated in vacuo to afford the 4-methyl-benzenesulfinic acid [2-(4-chlorophenyl)-1-cyano-2-methyl-propyl]-amide as a colorless oil (9.55 g, 95% yield). The material was heated to 110° C. (reflux) in concentrated HCl solution over the weekend. The solution was cooled to room temperature, washed with ether, then concentrated in vacuo to give the (S)-2-amino-3-(4-chlorophenyl)-3-methyl-butyric acid hydrochloride salt a white solid (1.61 g, 21%). 1H NMR (DMSO-d6, 400 MHz) δ 8.19 (brs, 1H), 7.48 (d, J=8.0 Hz, 2H), 7.41 (d, J=8.0 Hz, 2H), 7.13 (s, 3H), 4.15 (s, 1H), 1.42 (s, 3H), 1.40 (s, 3H). LCMS (APCI+) m/z 228 [M+H]+; Rt=1.81 min.

Provenance & Evidence