Dimethyl Sulfide → (2r,3s)-3-(Tritylamino)pentan-2-ol

Participants

Reaction Steps

To a stirred suspension of CuBr.SMe2 (3 g, 14.6 mmol) in anhydrous ether (100 ml) under an argon atmosphere at −78° C., was added methyl lithium (1.6M in ether, 16.5 ml, 4.0 eq, 26.5 mmol) dropwise and the solution allowed to warm to room temperature over 1 h. The mixture was recooled to −78° C., and a solution of (S)-2-(trityl-amino)-butyraldehyde (2.2 g, 6.62 mmol) in ether (25 ml) was added dropwise with stiffing. The reaction mixture was stirred at this temperature for 2 h then allowed to warm to room temperature over 1 h. A saturated aqueous solution of NH4Cl (50 ml) was added and the two layers separated. The organic phase was washed with brine (50 ml), dried (MgSO4) and evaporated in vacuo. The residue was purified by flash silica gel column chromatography, eluted with hexane:ethyl acetate (80:20) to afford (2R,3S)-3-(trityl-amino)-pentan-2-ol as a light yellow oil; Yield: 1.5 g (66%). (75% de 2R, 3S: 25% de 2S, 3S). 1H-NMR (d6-DMSO, 250 MHz): δ 0.0.47+0.55 (2×t, J=7.50+7.26 Hz —NHCH(CH2CH3)CH(CH3)OH), 0.99-1.12 (m, 5 H, —NHCH(CH2CH3)CH(CH3)OH), 2.01 (1 H, m, —NHCH(CH2CH3)CH(CH3)OH), 3.22-3.43 (m, 1H, —NHCH(CH2CH3) CH(CH3)OH), 4.41 [1 H, d, J=3.3, NHCH(CH2CH3)CH(CH3)OH], 7.14-7.56 (15 H, m, ArH). δC (250 MHz, CDCl3) 146.88 (C), 128.97 (6×CH), 127.83 (6×CH), 126.43 (3×CH), 71.03 (C), 68.13 (CH), 58.77 (CH), 23.09 (CH2), 17.88 (CH3), 10.47 (CH3)

Provenance & Evidence