Reaction Steps
Trichloromethyl chloroformate (5.4 g, 27.3 mmol) was added to a mixture of (S)-2-amino-1,1-diphenyl-3-methylpentan-1-ol 13 (4.97 g of 60%, 11.1 mmol) and triethylamine (5.3 g, 52.0 mmol) in CH2Cl2 at 0° C. The reaction mixture was stirred for 3 h at 0° C., then allowed to warm to room temperature for 18 h. The mixture was then washed with HCl (3×100 ml) and water (2×100 ml) and dried over MgSO4. Concentration gave a crude product, which was washed with diethyl ether to afford the title compound 14 (2.7 g, 83%) as a white amorphous solid. m.p. 221–223° C. [α]D25=−243.9° (c, 4.33 in CHCl3). δH 0.41 (3H, t, J=7.2 Hz, CH3), 0.80 (3H, d, J=6.9 Hz, CH3), 0.80–0.96 (1H, m, CH2), 1.18–1.32 (1H, m, CH—Me), 1.34–1.50 (1H, m, CH2), 4.27 (1H, d, J=3.6 Hz, CH—NH), 6.98 (1H, s, NH), 7.10–7.50 (10H, m, Ar—H). δC 11.3 (CH3—CH2), 17.2 (CH3—CH), 22.7 (CH2), 36.3 (CH—Me), 66.1 (CH—NH), 89.5 (C), 125.9, 126.5, 127.7, 128.0, 128.3, 128.6, 139.3, 144.0 (Ar), 159.1 (C═O). νmax (cm−1): 3281, 3162 (N—H), 3058 (Ar C—H), 2980, 2960, 2933, 2877 (methyl and methylene C—H), 1760, 1725 (C═O), 1493, 1448 (Ar C═C), 1243 (C—O). m/e 313 (MNH4+, 6%), 296 (MH+, 8%), 237 (100%).
