A highly enantioselective Michael addition of allomaltol (5-hydroxy-2-methyl-4H-pyran-4-one) to both aromatic and aliphatic β,γ-unsaturated α-ketoesters has been realized. Under the catalysis of a chiral bifunctional tertiary amine-squaramide that bears a (1R,2R)-1,2-diphenylethane-1,2-diamine scaffold, the reaction proceeded smoothly with high levels of enantioselectivity to give the desired products in acceptable yields with 86–>99 % enantiomeric excess. This methodology provided an efficient process for the enantioselective synthesis of optically active kojic acid derivatives.
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