Stereocontrolled Construction of Quaternary Stereocenters by Inter- and Intramolecular Nitro-Michael Additions Catalyzed by Bifunctional Thioureas
作者:Rubén Manzano、José M. Andrés、María D. Muruzábal、Rafael Pedrosa
DOI:10.1002/adsc.201000612
日期:2010.12.17
A highly diastereo- and enantioselectiveconjugateaddition of β-keto esters to nitroolefins, catalyzed by a chiral thiourea prepared from L-valine is described. The formation of two contiguous tertiary and quaternary stereocenters occurs in high yield and excellent diastereo- and enantioselection with only 2 mol% of catalyst loading. The reaction is general and different β-keto esters and aryl- and