Enantioselective Michael Addition of Photogenerated o-Quinodimethanes to Enones Catalyzed by Chiral Amino Acid Esters

The first example of a photoexcitated amine-catalyzed process for asymmetric Michael addition of o-quinodimethanes to enones is described. In the presence of simple chiral amino acid esters, a variety of Michael adducts were generally obtained in good yields and excellent stereoselectivities. This strategy can be successfully applied to 3-substituted-2-cyclohexenones and provides an asymmetric access to all-carbon quaternary centers. Furthermore, the high stereocontrol was explained by means of density-functional theory (DFT) calculations.