2-Thiophenecarboxaldehyde → trans-3-Thiophen-2-yl-oxirane-2-carboxylic acid ethyl ester

Reaktionsgleichung

[S:1]1[CH:5]=[CH:4][CH:3]=[C:2]1[CH:6]=[O:7].Cl[CH2:9][CH2:10][O:11][C:12](=[O:14])[CH3:13].CC[O-].[Na+]>CCOCC>[CH2:10]([O:11][C:12]([C@H:13]1[C@H:6]([C:2]2[S:1][CH:5]=[CH:4][CH:3]=2)[O:7]1)=[O:14])[CH3:9]

Komponenten

Versuchsvorschrift

The title compound was synthesized using a literature method (Alcaide, B.; Biurrun, C.; Martinez, A.; Plumet, J. Tetrahedron Lett. 1995, 36, 5417). To a solution of thiophene-2-carboxaldehyde (6.33 ml, 69 mmol) and chloroethylacetate (7.35 ml, 69 mmol) in 130 ml of ether was added freshly made NaOEt (4.7 g, 69 mmol) over a period of one hour. The solution was allowed to stir overnight at room temperature. The reaction mixture was then filtered and the filtrate was partitioned between water and ether. The ether layer was extracted and washed with water, brine, dried over MgSO4 and concentrated under reduced pressure. The residue was subjected to silica gel column chromatography (10% EtOAc in hexanes containing 1% NEt3, Rf=0.55). The title compound was isolated as a red oil in 64% yield. 1H NMR (CDCl3, 200 MHz) δ:7.30 (d, J=5.0 Hz, 1H), 7.17 (d, J=3.4 Hz, 1H), 6.99 (dd, J=5.0 Hz, 3.4 Hz, 1H), 4.33 (s, 1H), 4.28 (qd, J=7.0 Hz, 2.0 Hz, 2H), 3.68 (d, J=2.0 Hz, 1H), 1.33 (t, J=7.0 Hz, 3H) ppm. 13C NMR (CDCl3, 100 MHz) δ: 168.0, 138.6, 127.5, 127.4, 126.3, 69.1, 57.5, 54.9, 14.3 ppm.