[CH3:1][C:2]1[C:3](=O)[C:4]([O:10][CH3:11])([O:8][CH3:9])[C:5]=1[O:6]C.[CH3:13][O:14][C:15]1[CH:16]=[C:17]([Mg]Br)[CH:18]=[CH:19][CH:20]=1.C(OC(C(F)(F)F)=O)(C(F)(F)F)=O>C1COCC1>[CH3:1][C:2]1[C:5](=[O:6])[C:4]([O:10][CH3:11])([O:8][CH3:9])[C:3]=1[C:19]1[CH:18]=[CH:17][CH:16]=[C:15]([O:14][CH3:13])[CH:20]=1A THF solution (12 mL) of known 2-methyl-3,4,4-tris(methyloxy)-2-cyclobuten-1-one (0.500 g, 2.91 mmol, 1 equiv) was cooled to ca. −78° C. 3-Methoxyphenyl magnesium bromide (4.36 mL, 1.0 M, 1.5 equiv) was added. After 5 min, TFAA (0.657 mL, 4.66 mmol, 1.6 equiv) was added. The reaction was quenched with saturated NaHCO3 (5 mL) after an additional 5 min. Extraction with EtOAc was followed by drying (Na2SO4), filtration, and concentration to a bright yellow oil. Radial chromatography (SiO2, 4 mm plate, 80:20; hexanes/EtOAc) afforded the title compound (245) as a bright yellow oil (0.540 g, 75%). 1H NMR (CDCl3, 300 MHz) δ 7.44-7.33 (m, 3H), 7.15-7.09 (m, 1H), 3.89 (s, 3H), 3.54 (s, 6H), 2.13 (s, 3H). TLC (60:40; hexanes/EtOAc): Rf=0.45.
Wird geladen…
