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‐organo catalysis has been known for decades, the use of chiral C3‐symmetric multi–amino catalysts in asymmetric synthesis is not widespread. Herein, we extended the approach previously employed for the chiral 1,2‐diamino‐cyclohexane to the enantiopure 1,2‐diphenylethylendiammine. The independent activity of each catalytic subunit was also confirmed for this enantiopure motif by offline high‐resolution ESI‐MS experiments. We evaluated 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). In the pool of synthetized molecules, there are two novel compounds, and one was prepared for the first time using organocatalysis. In addition, some of these molecules showed an intrinsic scavenging ability on ABTS•+ radical.