Dimethyl Sulfoxide → (S)-2-(tritylamino)butanal

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

To a stirred solution of dry dimethylsulfoxide (2.4 ml, 2.8 eq, 33.82 mmol) in dry dichloromethane (30 ml) under an argon atmosphere at −78° C., was added oxalyl chloride (2M solution in DCM, 8.45 ml, 1.40 eq, 16.9 mmol), dropwise. The reaction mixture was stirred at −78° C. for 1 h, after which time a solution of (S)-2-(trityl-amino)-butan-1-ol (4 g, 1 eq, 12.07 mmol) in DCM (30 ml) was added dropwise with stirring. The reaction mixture was stirred at this temperature for 2 h after which was added a solution of triethylamine (TEA, 8.4 ml, 5 eq, 60.27 mmol) in DCM (30 ml), and the solution allowed to warm to room temperature over 1 h. The reaction mixture was diluted with more DCM (100 ml) and washed with water (250 ml). The aqueous phase was extracted with DCM (3×50 ml), and the combined organic phase washed with brine (50 ml), dried (Na2SO4) and evaporated in vacuo. The residue was purified by flash silica chromatography (ethyl acetate:Hexane 1:4) to afford (S)-2-(trityl-amino)-butyraldehyde as a light yellow oil; Yield: 3.64 g (91%). 1H-NMR (CDCl3, 250 MHz): δ 0.95 (3 H, t, J=7.5 Hz, —NHCH(CH2CH3)CHO), 1.72-1.52 [2 H, m, NHCH(CH2CH3)CHO], 2.76 (1 H, s, br, —NH), 3.41-3.36 [1 H, m, NHCH(CH2CH3)CHO], 7.35-7.17 (12 H, m, ArH), 7.67-7.51 (3 H, m, ArH), 9.05 (1 H, s, NHCH(CH2CH3)CHO). δC (250 MHz, CDCl3) 202.95 (CO), 146.23 (C), 129.23 (6×CH), 127.96 (6×CH), 126.85 (3×CH), 71.13 (C), 62.62 (CH), 24.78 (CH2), 10.48 (CH3)

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