Enantioselective Michael reaction of β-keto esters organocatalyzed by recoverable Cinchona-derived dimeric ammonium salts
作者:Silvia Tarí、Rafael Chinchilla、Carmen Nájera
DOI:10.1016/j.tetasy.2009.11.007
日期:2009.12
Dimeric anthracenyldimethyl-derived Cinchona ammoniumsalts are used as chiral organocatalysts in 1–10 mol % for the enantioselective conjugate addition of 2-alkoxycarbonyl-1-indanones to β-unsubstituted Michael acceptors. The corresponding adducts bearing a new all-carbon quaternary center were usually obtained in high yield and with up to 94% ee when using ammoniumsalts derived from quinidine and
Recoverable Cinchona ammonium salts as organocatalysts in the enantioselective Michael addition of β-keto esters
作者:Silvia Tarí、Rafael Chinchilla、Carmen Nájera
DOI:10.1016/j.tetasy.2010.11.016
日期:2010.12
Several dimeric Cinchona-alkaloid anthracenyldimethyl-derived ammoniumsalts, are used as organocatalysts in the enantioselective Michael addition reaction of cyclic β-ketoesters to α,β-unsaturated carbonyl compounds, in the presence of diisopropylethylamine as a base (30 mol %), for the generation of enantiomerically enriched adducts bearing quaternary stereocenters. Quinine and quinidine-derived