Because of the versatility of chiral 1,5-dicarbonyl structural motifs, the development
of stereoselective Michael additions of arylacetic acid derivatives to electron-deficient
alkenes is an important challenge. Over recent decades, an array of enantio- and diastereoselective
methods of this type have been developed through the use of chiral organocatalysts.
In this article, three distinct strategies in this research area are highlighted.
Catalytic generation of either a chiral iminium electrophile (iminium catalysis) or
a chiral enolate nucleophile (Lewis base catalysis) has allowed the efficient construction
of stereogenic C–C bonds. We also introduce a synergistic catalytic approach involving
the merger of these two catalytic cycles that provides selective access to all four
stereoisomers of products with vicinal stereocenters.
Key words
asymmetric catalysis - organocatalysis - Michael addition - iminium catalysis - isothiourea
catalysis - synergistic catalysis
