Asymmetric Addition of Allomaltol to Chalcones and Bis(arylidene)acetones: En Route to Chiral Drugs

Abstract The synthesis of enantiomerically enriched γ‐oxobutyric acid and succinic acid derivatives based on asymmetric conjugate addition of allomaltol to chalcones or bis(arylidene)acetones in the presence of readily available and recoverable C 2 ‐symmetric tertiary amine‐squaramide organocatalyst has been developed. Ru(III)‐catalyzed oxidative transformation of pyran‐4‐ones bearing the α,β‐enone unit to enantiomerically enriched succinic acid derivatives via a one‐pot oxidative fragmentation of both the γ‐pyrone ring and activated C=C bond has been elaborated. The developed methodology was applied for scalable asymmetric synthesis of GABA B receptor agonists precursors, RAR receptor agonists and monoaminooxidase (MAO) inhibitors.