The readily scalable asymmetric synthesis of the chiral chromone derivatives functionalized at position 2 via electrophilic enantioselective olefination of the chromone core with nitroolefins and ß,γ‐unsaturated α‐ketoesters in the presence of simple C2‐symmetric tertiary amine‐squaramide catalyst was developed. The reaction products were obtained in 80–99% yield with 89–99% ee in 95% EtOH. The absolute configurations of the synthesized chromone derivatives were unambiguously established by transformation of compound (R)‐3 aa to known methyl (R)‐β‐nitro‐α‐phenylpropionate and by the single crystal XRD analysis of compounds (R,S)‐5 aa and (R,S)‐5 ab. Catalyst V poorly soluble in common organic solvents could be easily separated from the reaction mixture and reused up to 10 catalytic cycles. Catalytic hydrogenation and esterification reactions of the synthesized compounds were carried out to demonstrate synthetic potential of the developed procedure.

2-Nitroallylic carbonates were first applied as promising biselectrophilic C3 synthons for bifunctional squaramide catalyzed asymmetric domino reaction with kojic acid derivatives to afford so far inaccessible nitro compounds bearing two hydroxypyranone units. The reaction products undergo noncatalytic epimerization at the carbon atom next to the nitro group. Plausible mechanism of the epimerization based on reversible formation of intermediate aci-nitro compound is proposed. The double addition products were transformed to configurationally stable acetates and to chiral nitro glutarates, promising precursors to chiral amino glutaric acid derivatives.

A bifunctional tertiary amine-squaramide catalyzed enantioselective Mannich-type addition of available allomaltol to N-protected aldimines was developed. The resulted adducts were readily transformed to nonproteinogenic α-amino acids and their derivatives not...