Enantio- and Diastereoselective Michael Reactions of Silyl Enol Ethers and Chalcones by Catalysis Using a Chiral Quaternary Ammonium Salt
作者:Fu-Yao Zhang、E. J. Corey
DOI:10.1021/ol015592k
日期:2001.2.1
[GRAPHICS]N-(9-Anthracenylmethyl)dihydrocinchonidinium bromide (1) is an effective catalyst for enantioselective Michael additions to chalcones, as shown in the above example, using toluene/50% aqueous KOH biphasic conditions at -20 degreesC.
Highly Enantioselective Michael Reactions Catalyzed by a Chiral Quaternary Ammonium Salt. Illustration by Asymmetric Syntheses of (<i>S</i>)-Ornithine and Chiral 2-Cyclohexenones
作者:Fu-Yao Zhang、E. J. Corey
DOI:10.1021/ol0056527
日期:2000.4.1
[formula: see text] The use of the chiralquaternaryammonium salts 1a and 1b makes possible enantioselective Michael reactions which have been applied to the asymmetric syntheses of (S)-ornithine (2) and the chiral 2-cyclohexenone 6.