A C3‐Symmetric Diphenylethylendiamine‐Based Catalyst in the Asymmetric Michael Addition of α,β‐Unsaturated Ketones with 4‐Hydroxycoumarin and 4‐Hydroxyquinolin‐2‐One

Even though the amino-organocatalysis has been known for decades, the use of chiral C3-symmetric multiamino catalysts in asymmetric synthesis is not widespread. Herein, the previously employed approach for the chiral 1,2-diamino-cyclohexane to the enantiopure 1,2-diphenylethylendiamine is extended. The independent activity of each catalytic subunit is also confirmed for this enantiopure motif by offline high-resolution electrospray mass spectrometry (ESI-MS) experiments. The advantages and limitations of this novel approach in the asymmetric Michael addition of α,β-unsaturated ketones to 4-hydroxycoumarin and 4-hydroxyquinolin-2-one, achieving up to 95% yield and moderate-to-good stereocontrol (enantiomeric ratio up to 80:20) are evaluated. In the pool of synthetized molecules, there are two novel compounds, and one is prepared for the first time using organocatalysis. In addition, some of these molecules show an intrinsic scavenging ability on ABTS•+ radical.