A kind of synthetic method of optically active 2-(2-nitro-ethyl)-pyrrole
A nitroethyl and pyrrole technology, applied in the field of 2-pyrrole compounds, achieves the effects of simple operation, mild reaction conditions and high enantioselectivity
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Embodiment 1
[0020] Embodiment 1: the preparation of chiral phosphoric acid
[0021] Under the protection of argon at room temperature, dissolve the derivative of BINOL (0.5mmol) in 1mL of dry pyridine in a dry reaction tube, and slowly drop (1.0mmol) of phosphorus oxychloride under the condition of rapid stirring Added to the system, stirred at room temperature for 3 hours. 1 mL of water was slowly added dropwise to the system, and stirred at room temperature for 30 minutes. Dichloromethane was added to dissolve, washed with 1N hydrochloric acid aqueous solution (10mL×3), the organic layer was dried over anhydrous sodium sulfate, the solvent was spun off under reduced pressure, and the residue was separated by column chromatography to obtain the product.
[0022] (S)-3,3'-[3,5-bis(trifluoromethyl)phenyl]2-1,1'-binaphthol phosphate
[0023] (S)-3,3′-[3,5-Bis(trifluoromethyl)phenyl]2-1,1′-binaphthyl phosphate
[0024]
[0025] Solid, 89% yield. IR (lamination method) 1620, 1501, 1474...
Embodiment 2
[0026] Example 2: Chiral phosphoric acid catalyzed addition reaction of pyrroles to nitroalkenes
[0027] Add (chiral) phosphoric acid compound (0.0015mmol), pyrrole compound (0.45mmol), benzene / dichloromethane 0.6mL and Molecular sieves (50-100 mg), under stirring at room temperature, slowly add nitroalkene compound (0.30 mmol) (dissolved in 0.6 mL benzene / dichloromethane) dropwise for 2 hours, and the product was separated by column chromatography.
[0028] P1: 2-(2-nitro-1-phenylethyl)-pyrrole
[0029] P1: 2-(2-nitro-1-phenylethyl)-1H-pyrrole
[0030] R f =0.40 (dichloromethane / petroleum ether=1 / 1, v / v); brown solid; 94% yield, 89% ee; 1 H NMR (400MHz, CDCl 3 )δ4.78(dd, J=11.9Hz, 7.6Hz, 1H), 4.86-4.89(m, 1H), 4.96(dd, J=11.9Hz, 7.3Hz, 1H), 6.06-6.08(m, 1H) , 6.14-6.17(m, 1H), 6.65-6.67(m, 1H), 7.20-7.24(m, 2H), 7.27-7.36(m, 3H), 7.82(br, 1H); 13 C NMR (100MHz, CDCl 3 )δ42.9, 79.2, 105.8, 108.6, 118.2, 127.9 (2C), 128.1, 128.9, 129.2 (2C), 137.9; IR (press film met...
Embodiment 3
[0082] Example 3: Conversion of 2-(2-nitroethyl)-pyrrole compounds
[0083] In an egg-shaped bottle, 2-(2-nitroethyl)-pyrrole compound (1mmol) was dissolved in acetonitrile (7mL), and NaIO was added at room temperature 4 Aqueous solution (0.06mmol / 21mL), stirred for 15 minutes after addition. Ruthenium trichloride compound was added and stirred for 2 hours, and the reaction was completed and extracted with ethyl acetate (3x10 mL). The combined organic layers were added with diethyl ether (15 mL) and stirred for several minutes. Anhydrous magnesium sulfate was added for drying, and the solvent was removed under reduced pressure, and the residue was separated by column chromatography to obtain a crude product. It was dissolved in tetrahydrofuran (0.5 mL), and oxalyl chloride (0.3 mmol) was added at zero temperature. After the addition, it was stirred at room temperature for 1 hour, and the solvent and excess oxalyl chloride were removed under reduced pressure. The obtained cr...
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