CC1C=CC(P(C2C=CC3C(=CC=CC=3)C=2C2C3C(=CC=CC=3)C=CC=2P(C2C=CC(C)=CC=2)C2C=CC(C)=CC=2)C2C=CC(C)=CC=2)=CC=1.[CH3:51][O:52][C:53](=[O:62])[CH2:54][CH2:55][C:56]1[CH2:60][CH2:59][C:58](=[O:61])[CH:57]=1.CCCCCC>C(OCC)(=O)C>[CH3:51][O:52][C:53](=[O:62])[CH2:54][CH2:55][CH:56]1[CH2:60][CH2:59][C:58](=[O:61])[CH2:57]1General procedure B using (S)-p-tol-BINAP and 3-(3-oxo-cyclopent-1-enyl)-propionic acid methyl ester (0.084 g, 0.5 mmol) gave, after 24 h at 0° C. and flash chromatography (4:1, then 2:1 hexane:ethyl acetate), the title compound as a clear oil (0.075 g, 88% yield). Spectroscopic data were consistent with previously reported data for this compound.15 [α]D25° C.−112° (c 1.3, CHCl3). Conversion of the title compound to the corresponding benzyl ester followed by chiral HPLC analysis (Chiracel OD column) indicated that the title compound was obtained in 91% ee.
Wird geladen…
